What’s this blog about…?

February 16, 2012

I wanted to document my efforts in fixing up a 1997 Volvo 850 wagon to help my three children understand and appreciate what it takes to get an older car fully functional and running reliably.  They may be doing something like this for themselves in the future, so this blog is for their reference.  If it helps other Volvo 850 owners along the way, all the better.

Parts and labor at most shops–Volvo dealers in particular–are very costly.  This effort approaches reasonable economy if you do it yourself (DIY), so most everything shown was done at home where labor is free.  Cost of parts is given at the end of each task.

Postings are presented in order of task performed with most recent at top.  Seemingly random, I did these tasks as time, parts and weather permitted and issues were observed.  Previous owners had some work done already so I did not need to tackle those items which might seem more urgent (brakes, tires, struts).

Note:  This is not a step-by-step repair document.  It shows only the basic task accomplished.  There are plenty of internet repair forums for this.  However, many posts are detailed and somewhat educational (explanation of what/why/how).  I don’t pretend to be an expert or authority on Volvos; this blog is just sharing my experience and opinions with my kids and other readers.

Jim Peisker  |  Cedar Park, Texas

Sagging Bumper Repair

July 11, 2015

So the white sedan got kissed from behind in our neighborhood.  No real damage because the car that hit it was barely moving but strong enough to jolt my daughter and make the rear bumper sag just enough to look not quite right.

Permanent rear bumper sag due to minor rear-end collision.

Permanent rear bumper sag due to minor rear-end collision.

The damage is really minor and we could live with it but it does look funny; slightly worse in person than what is shown in the photo above.  I researched this online and learned that 850s have bumper mounting brackets that corrode and weaken over time and sometimes the bumper sags with little or no force, and minor accidents cause them to really bend.

Anyway, without disassembling this car I felt confident that these brackets were the problem so ordered them (both left and right) and had the lady who hit the car pay for the parts.

The bumper assembly is secured with only four bolts plus six rivets.  To get to one of the main bolts requires removal of the exhaust tip (tail pipe) and that was the one thing I was most concerned about.  My experience with the red wagon project car with the tail pipe was that it broke when I removed it.  So I began the project with this part knowing it was the most likely to cause trouble and delay the project.

DSCN3973

Tail pipe needs to be removed to allow the long bumper bolt above it to drop down.

Gave the fixing bolt a shot of PB blaster penetrating oil the night before to help break it loose.

Tail pipe removed for bumper bolt extraction.

Tail pipe removed for bumper bolt extraction.  You can see the dimple in the exhaust tube where the fixing bolt held the tip in place.

I carefully and slowly loosened the exhaust tip bolt to avoid shearing it off as they tend to get corroded and weak with moisture and heat over time.  Fortunately it remained strong and solid so I was able to twist the pipe off the exhaust tube.

Next up was removal of the rivets securing the front-facing edges of the bumper assembly to the rear wheel liners.  I thought I would be clever and avoid the hassle of removing the wheels to do this.  With limited space I managed to cut through the plastic-coated aluminum rivets using an old wood chisel and hammer.  It worked pretty well.

Shearing the heads off the wheel liner rivets with a hammer and chisel.

Shearing the heads off the wheel liner rivets with a hammer and chisel.

Head removed from first rivet.

Head removed from first rivet.

All three rivets removed from one side.

All three rivets removed from one side.  Bumper is now held by two large and two small bolts.

Separated bumper from wheel liners on both sides (six rivets total) so the front-facing edges were free.

Next we removed the side fixing bolts.  On the left side the trunk (boot) liner had to be moved to get to the nut.  This takes a little bit of fussing but only three twist fasteners had to be removed.

Left side nut accessed by moving trunk liner (three twist fasteners).

Left side nut accessed by moving trunk liner (three twist fasteners).

Left side bumper nut removed.  Stud protruding through wall connects to bumper side.

Left side bumper nut removed. Stud protruding through wall connects to bumper side.

It’s different on the right side.  Here the side nut is accessed not through the trunk but from underneath near the fuel filler tube.

Right side bumper nut loosened from underneath car, ready to spin off.

Right side bumper nut loosened from underneath car, ready to spin off.

After removing these two nuts the sides of the bumpers were free and I pulled them out.  The side attachment bolts are tied to plates which slide in slots in the bumper, which allows some front-back movement.

Finally we remove the two long vertical bolts which hold the bumper to the mounting brackets.

Remove two bolts which secure the bumper assembly to the mounting brackets.

Remove two bolts which secure the bumper assembly to the mounting brackets.

After removal of these two long bolts the bumper is now free to pull off the car.  It is sort of wedged between the top and bottom bracket flanges.

Main bolts removed, ready to pull bumper off.

Main bolts removed, ready to pull bumper off.

Bumper pulled off.  Not very heavy (less than 20 pounds).

Bumper pulled off. Not very heavy (less than 20 pounds).

DSCN3988

Here are the problematic bumper brackets that are slightly bent from the rear-end collision.

Here are the problematic bumper brackets that are slightly bent from the rear-end collision.

You can see from this mounting bolt position in the lower hole how the bracket is slightly bent in and down, which is why the bumper sagged.

You can see from this mounting bolt position rearward in the lower hole how the bracket is slightly bent in and down, which is why the bumper sagged.

Now on most 850s these brackets are badly corroded and weak.  In this case the brackets are in rather good condition, considering they are factory original.  It helps that this car has lived its 18 year life inland in mild climates (California and Texas) where roads are not salted and there is no ocean air.

At this point I could attempt to straighten them out a little since they are not badly bent.  However, we already have the parts in hand and new parts will be stronger and more reliable long-term, so they were replaced.

Bent brackets removed.

Bent brackets removed.

Old and new parts compared side-by-side.

Old and new parts compared side-by-side.

At this point, assembly is basically reverse of the removal procedure (don’t you love seeing this phrase in instructions?)  I re-used the mounting bolts to attach the new brackets to the frame since they were in good condition.  The bracket mounting holes are fairly large to allow for up/down/left/right movement.  I used the dirt marks on the frame to line things up horizontally and pushed the brackets up as high as they would go.  Note that the brackets want to wander when you tighten the bolts so I had to hold them tightly to keep in place.  If the bracket is badly corroded as many people find, all associated bolts may also be in bad condition and should be replaced.

After pushing the bumper back into place I started by pushing the side bolts through their respective openings and spun nuts loosely on to keep them in place while moving the rest of the bumper around.  This is the only tricky part of the job and it’s really not hard at all once you figure it out.

Next I secured the bumper in place; re-used the long bumper fixing bolts after cleaning them up since they were in very good shape.

Re-used original mounting bolts after cleaning the threads.

Re-used original mounting bolts after cleaning the threads.

Getting the holes in the bumper to line up with the bracket took a little manipulation.  Had to tap on the bumper a bit to move things into place but once it got close the bolt lined up nicely.

After securing the main bolts I tightened the side nuts and put the trunk lining back in place on the left side.

To make the car safely drivable I re-installed the exhaust pipe by slipping it back into place and tightening the fixing bolt.

The last part is where things didn’t go as planned.  I had intended to avoid removing the wheels (which is why I chiseled the rivet heads off) and use these “Christmas Tree” push-in fasteners instead, which required little clearance.  However, I found that the ones I bought (5/16″ dia [7.9mm]) were just a little too large in diameter to fit into the bumper hole.  I could not push them through to secure the two pieces together.  My guess is that 1/4″ fasteners would work since these almost fit, but I didn’t have any of these.  So I had to go with plan B…

Black nylon push-type wheel arch retainer clip (christmas tree style) was a good idea but slightly too large for the hole in the bumper; could not force it in.

5/16″ push-type retainer (christmas tree style) was a good idea but slightly too large for the hole in the bumper; could not force it in.

Close but not quite.  Could not push these fasteners all the way in to secure the bumper.

Close but not quite. Could not push these fasteners all the way in to secure the bumper.

Plan B involved using the proper rivets to secure the wheel liner to the bumper.  Unfortunately the clearance required for the rivet and the tool demands that the wheel be removed.  Since I had to remove the wheel, I could have just drilled the rivets out as we would normally do.

Genuine Volvo wheel liner rivet requires common rivet tool.

Genuine Volvo wheel liner rivet requires common rivet tool.  You can use normal aluminum rivets but these really stand out against the black liner.  I suppose black nylon rivets would also work since there is not a strong mechanical load on these parts.

Wheel liner properly riveted to bumper, three per side.

Wheel liner properly riveted to bumper, three per side.  Wheels must be removed for clearance to install the rivets.

So I had it all back together and now it looks just like it should:

Yay!  The bumper is back in its rightful place after replacing the bent mounting brackets.

Yay! The bumper is back in its rightful place after replacing the bent mounting brackets.

Project took only a couple of hours and was less work than I anticipated after looking at instructions.  It was easier than I expected and everything went smoothly (for once, no big surprises), which was a blessing on this hot Texas summer day.

Here is a good writeup on MVS.  The procedure shows the bracket corrosion more commonly found on these cars.

And for a dose of humor, I will sign off with this:  My baby drives the car which might be called a buggy in some cultures and the bumpers have some elastic material in them, so I can officially say that today I worked on rubber baby buggy bumpers.

$49.39 for factory replacement bumper brackets

Note that there are different part numbers for left and right and also differences between wagon and sedan brackets.

Corner Light Epidemic

July 8, 2015

Well, just like the project car red wagon, the white 850 sedan lost its right front corner light (front parking/turn signal lamp) lens.  You can read up on the details in task #98 from last spring.  Based on feedback from some readers plus this experience, I’m ready to pronounce this common problem to be a plague or epidemic and recommend that all 850 owners check theirs and repair as needed.

Like the red wagon experienced last spring, the front right corner lens fell off somewhere down the road.

Like the red wagon experienced last spring, the front right corner lens fell off somewhere down the road.

It seems pretty obvious that the adhesive weakens and vibration causes the lens to drop off while driving; it’s gone forever unless you happen to know when and where it launched.  18+ years of heat and sunlight cause the glue to dry out and lose its grip on the lens.

Lens adhesive gets hard and crusty over time and loses grip on the lens.

Lens adhesive gets hard and crusty over time and loses grip on the lens.

New light assembly installed.  Easy and looks great.

New light assembly installed. Easy and looks great.

Because both 850s lost lenses I thought I should check the lenses on the left side of both cars.  The red wagon’s lens was secure but this white sedan’s lens popped off with almost no effort.  So it was due to fall off on its own, part of the reason I termed this an epidemic.

Left side corner light lens popped off while gently tugging on it.  Was ready to fly off on the road.

Left side corner light lens popped off while gently tugging on it. Was ready to fly off on the road.

The good news here is that the lens didn’t fly off while driving so we can repair it to save the expense of replacing the whole light assembly.

I used some clear silicone adhesive caulk to glue the lens back on the assembly and let it cure for a while while clamped.  Just for grins I tugged on it to make sure it would stay attached.

Glued lens back on assembly using clear silicone adhesive caulk and clamped it while curing.

Glued lens back on assembly using clear silicone adhesive caulk and clamped it while curing.

Repaired (glued) light assembly re-installed.

Repaired (glued) light assembly re-installed.

My recommendation for all 850 owners is to tug on their corner lights lenses to make sure they are secure.  This is best done with the hood (bonnet) lifted up for better grip.  If they are loose or pop off, congratulations!  You saved the expense of buying a new light assembly.  All you need do is glue it back on.

#113 Darken Bumpers

June 9, 2015

With time, weather, and sunlight, the dark gray trim on these 850s starts to fade.  The large surface area on the textured bumpers gets particularly ugly with an uneven, splotchy appearance.

Uneven fading of bumper tops, typical of older 850s.

Uneven fading of bumper tops, typical of 850s now 18+ years old.

There are various products and methods for improving the look of these faded surfaces.  I wanted to report the results after trying WipeNew on the bumpers.  WipeNew is relatively inexpensive and easy to apply.  Basically you wipe it on and the chemistry reacts with polymeric surfaces to make them appear both darker and shinier.

More specifically, the 20 year-old daughter who drives the car does the work while you relax indoors with a cold beverage.  Let youth and chemistry do the job.

Small bottle of WipeNew product was more than enough to cover bumpers and other exterior trim.

Small bottle of WipeNew product was more than enough to cover bumpers and other exterior trim.

Applying WipeNew with rag towel.  You can see the difference between the treated area vs. unfinished.

Applying WipeNew with rag towel. You can see the difference between the treated area on left vs. unfinished.

This shows a dramatic difference with the untreated area under the sheet metal.  Could have reached under there with a swab but didn't want to go to the trouble.

This photo shows significant improvement; see untreated area under the sheet metal. Could have reached under there with a swab but didn’t want to go to the trouble.

Before

Before

After

After.  Looks darker when viewed in person; camera exposure minimizes contrast.

The results are OK, in my opinion.  Not horrible but not spectacular, either.  The bumpers (and dark gray trim elsewhere) are darker and shinier, more like new.  But they aren’t exactly like new.  I wasn’t expecting miracles so wasn’t disappointed.  Generally happy; it’s certainly an improvement.  Perhaps a second application in the near future will improve the look even further.

$13 for WipeNew kit (product plus application accessories)

Back in Action, Mostly

June 9, 2015

Well, I’m now physically able to do some things on these 850s.  My case of spinal stenosis required back surgery which went well.  Several weeks out now I am mostly functional but my lower back is still stiff and sore.  It will take some time for the back to heal up completely.  I’m not ready yet for any major jobs that require a lot of exertion or contorting my body but there are a few things we can do.

So you will see a few more posts this summer.  Speaking of summer, it quickly set in here in Central Texas.  After record-setting rainfall for the month of May, we’re drying out now and heating up– seasonably warm here.  Local flooding also tied me up helping with emergency communications and disaster relief since I’m a ham radio operator supporting two local agencies.

A couple of cosmetic things coming up.  Then an interesting topic of replacing brackets to fix a sagging rear bumper.  Still chasing a small evaporative emissions leak.

To the many new followers of this blog who haven’t seen much activity lately, let me explain a few things–

First, with 112 tasks completed as repair or maintenance items on the project car, we’re running low on things to do.  Of course, since the car is 18 years old now there are more things to fail.  But we’ve done almost all of the common repairs and replacements plus many other little problems that the 850 throws out.  We haven’t yet had to replace the fuel door hinge or fix the horn button or repair/replace the PNP switch; those are all common problems with 850s.  I’m sure we will find more in time.

Second, my health and the weather (cold winter, wet spring) has limited what we can do.  Thankfully the car is in fairly good working order; nothing to keep it off the road.

Lastly, for those of you who only see this blog via email, you may not know you can click to the home page.  There you will see categories to search for particular topics.  That’s a quick way to jump to a post of particular interest or browse for something that might interest you.

Thanks for reading, and have a great summer!

Jim

Rear Main Seal Failure and Clutch Replacement

March 28, 2015

Now don’t get too excited to learn much DIY here– this was a situation for an independent shop so the car was worked on there.  But both issues are a common occurrence on Volvo 850s and I wanted to share what I know.

One day I noticed that the white 850 sedan (not the red wagon project car) had a big dark spot under the front end and I went looking for trouble.

Remnant of oil puddle on driveway under engine.

Remnant of oil puddle on driveway under engine.

My worst fears were confirmed after verifying that it was, unfortunately, the rear main seal that was leaking.  No other fluids were low except the oil.  Also, I checked that oil wasn’t leaking down from the camshaft end seals near the top of the engine, which tends to drip directly down to the same area, giving an appearance of a main seal leak.

The car had 174662 miles on it (281091 km) so it’s no surprise that this seal wore out.  The rear main seal (RMS) prevents oil loss from the engine where the crankshaft (engine output) protrudes from the engine.  Because the crankshaft is constantly rotating, the seal will wear out eventually; the sealing material will naturally disintegrate over time.  I think this car did well to last 175K miles on the original RMS.

There appears to be a weep hole just below the transition from the engine to the transaxle.  That is where I saw a lot of dark oil dripping out.  My guess is that this opening was deliberately put there by Volvo to detect a seal leak.

Weep hole between engine and transmission visible in reflection on inspection mirror.

Weep hole between engine and transmission visible in reflection on inspection mirror.

In this situation I know it requires removal of the transaxle to access the rear main seal for replacement.  That’s a big job and done right it requires special tools, lifting equipment, and room to maneuver.  Plus it takes a fair bit of time and in my current physical condition I really couldn’t see tackling this on my own.  Hurts me to say so since I am really keen on DIY.  People have done the work themselves and have posted the procedure on forums [one good one is here ] but I chose to take it to a shop.  ($$$)

Anyhoo, to add insult to injury, the clutch started acting badly according to my daughter.  This car has a manual transmission which has always felt or behaved erratically since we inherited the car.  [This is my chance to rant and get it off my chest–  Why my father-in-law went out of his way to buy a car with a stick shift when he worked in San Francisco (famous for steep hills) is beyond me!]  The only saving grace is that the bulk of the labor for these two jobs is the same.  Both require removal of the transaxle, for which labor is the most significant cost.  Therefore it makes sense for the RMS to be replaced when you do a clutch job and perhaps replace the clutch when you do the RMS, depending on wear.

After driving it the shop technician wanted to replace the engine flywheel as well because by feel and experience he suspected it was damaged.  Because we were traveling and had time to leave the car with the shop, I negotiated that they inspect the flywheel before ordering one (factory part only at about $500!)  Good news in the end was that the flywheel was not badly damaged and only needed some machining to resurface it for about $100.

Got the car back with new main seal and clutch.  No more oil leak and the clutch now operates better than when we inherited the car; it’s quite nice to drive.

I am aware that rear main seal leakage is a symptom of a clogged PCV system (oil separator and flame trap on 850s).  To make sure this wasn’t an issue, I checked the car for this condition by putting a latex glove tightly over the dipstick tube and verifying that it did not inflate, which would indicate a pressurized crankcase (plugged PCV).

Glove (or balloon) tightly coupled to dipstick tube did not inflate.  If it had, it would indicate that the crankcase was being pressurized.

Glove (or balloon) tightly wrapped around dipstick tube did not inflate. If it had, it would indicate that the crankcase was being pressurized.

Also checked that there was no smoke coming from the dipstick tube, which is another indicator of the same problem.

No smoke from the dipstick tube.  Good indication that the crankcase is not pressurized.  Smoke usually means the PCV system is clogged and can lead to oil seal failures all around the engine.

No smoke from the dipstick tube. Good indication that the crankcase is not pressurized. Smoke usually means the PCV system is clogged and can lead to oil seal failures all around the engine.

Since the red wagon has nearly the same mileage, we’ll have to keep an eye on it for the RMS leak.  Hope the project car lasts even longer than this one!

$1778 for new RMS, clutch kit (pressure plate, disc and the throw-out bearing).  Of this, nearly $1000 is labor.

Not Much Happening Right Now…

March 10, 2015

Sorry it’s been a good long while since I posted anything.  The car has mostly been off to college since early fall and when it has been here the weather has been uncooperative.  It’s dark outside when I get home from work so Saturdays are the only day I have to mess with the cars, and those are often busy.

Another factor is that I am dealing with a physical problem that limits my movement and comfort.  Spinal stenosis in the lumbar region frequently gives me a lot of pain in my lower back and upper legs.  So I haven’t been in good shape to work on these 850s even if I had the occasion.

Anyway, daylight saving time just bought us an extra hour of daylight and the weather will be warming up.  When the red wagon is here I plan to tear into the evap lines to fix a small leak that’s trowing a trouble code once in a while.  Also some cosmetic things including re-covering the roof trim strips with flat black coating.  The dash pad needs to be better secured and I’m sure something else will need fixing by then.  Probably fool with the engine torque mounts to minimize vibration (go back to rubber instead of polyurethane?)

On the white sedan I need to replace the control arms and there is a big issue with the clutch and rear main oil seal.

Stay tuned; you never know what will happen next with two 1997 Volvo 850s!

#112 Engine Sub-frame Mount Bushing Inserts

December 26, 2014

I’ve had these sub-frame bushing inserts laying around for months before I finally got around to installing them.  IPD has several unique Volvo 850 products that are really good and this is one of them.

IPD sub-frame bushing kit includes four PE inserts, two tubes of lubricant and one small tube of thread locking compound.

IPD sub-frame bushing kit includes four PU inserts, two syringes of lubricant and one small tube of thread locking compound.

The general idea is that these inserts tighten up the engine sub-frame mounting bushings that degrade over time.  Users have reported a big improvement in steering and handling in general.

Polyurethane (PU) insert tightens up existing sub-frame bushing.

Polyurethane (PU) insert tightens up existing sub-frame bushing.

850 engines sit on a separate sub-frame which is then connected to the car chassis via mounting bushings on four corners.  These bushings are made of rubber and give some of the same vibration isolation that the main engine mounts do.  Over time rubber degrades and depending on mileage, driving conditions and chemical exposure these sub-frame mounts can get really sloppy.  The whole engine sub-frame can move front to back and side to side a little compared to new bushings.  Symptoms of worn bushings include clunking noise, uneven tire wear, steering play/movement and steering influenced when accelerating or braking.

Replacing the mounts is both expensive and time-consuming.  IPD came up with this reasonably priced solution that takes only an hour or two to install.  They fill in the gaps of the original bushings to tighten them up and give a factory-new feel.

Start by lifting the front of the car.  This can be done with wheels on so this is a good time for ramps.  You work on the four bushings one at a time so that the sub-frame doesn’t need extra support.  I started with the front right as shown.  The process is presented below.

Driving the car up on ramps gives good access to the front bushings and adequate room for the rear.

Driving the car up on ramps gives good access to the front bushings and adequate room for the rear.  Don’t forget to chock the rear wheels.

Front bushings tackled first.

Front bushings tackled first.

Large, long bolt removed.  Bushings now viewed clearly.

Large, long bolt removed. Bushings now viewed clearly.

Half of the lube per syringe is squirted into the voids where the inserts will be placed.

Half of the lube per syringe is squirted into the voids where the inserts will be placed.

Insert pressed into place in bushing.  In this case the bushings were in good condition and I had to hammer them in with a rubber mallet.

Insert pressed into place in bushing. In this case the bushings were in good condition and I had to hammer them in with a rubber mallet.

New bolts are recommended for reattachment but this is not always practical.  IPD provides a small amount of thread locking adhesive for more security when the original bolts are re-used.

New bolts are recommended for reattachment but this is not always practical. IPD provides a small amount of thread locking adhesive for more security when the original bolts are re-used.

Original bolt secured to torque specification with thread locking adhesive.  One front corner complete.  Repeat for other side.

Original bolt secured to torque specification with thread locking adhesive. One front corner complete. Repeat for other side.

For the front bushings I found that the engine dropped a bit too much so supported the sub-frame with a floor jack.  This was not necessary for the rear bushings.

For the front bushings I found that the engine dropped a bit too much so supported the sub-frame with a floor jack. This was not necessary for the rear bushings.

Rear bushings treated the same way with an additional step of unbolting the delta-frame plate from the chassis.

Rear bushings treated the same way with an additional step of unbolting the triangle-shaped frame plate from the chassis.

After installing the inserts on all four corners I drove the car off the ramps and took it for a test drive to see if things had changed.  There is a slight improvement in steering feel/play but nothing dramatic.  In the case of this project car the original bushings were in surprisingly good shape after 18 years.  In fact, I had a hard time pressing the inserts into the bushings which indicated the rubber was still fairly intact and strong, plus we had no significant issues with steering or vibration.  Surely there are many older 850s out there with really worn bushings because there are a lot people who report a big improvement after installing these.  I don’t regret doing this job on this car because it is preventive maintenance so we shouldn’t need to deal with these in the future.

IPD recommends checking front end alignment when sub-frame bushings are worked on as the steering gear/rack might have moved a small amount.

Details and ordering info on the IPD website.

$59.95

#111 Exhaust Rattle

November 30, 2014

The last thing I looked into while the car was home this past weekend is a rattling noise under the car.  It happened only when the car was in drive (automatic transmission) and the brakes were applied.

This symptom told me the problem was related to the slight shift in engine rotation when the car is in drive.  Reference post #105 to learn how the engine tilts to the back when in drive and the car is not moving.

Because the rattle is not heard when the transmission is in reverse, park or neutral, it also means that it is a very slight amount of engine rotation that causes metal-to-metal contact.

So I went looking for possible exhaust contact points under the car with the front up on ramps.

I spotted a heat shield just under the pipe connecting the exhaust manifold to the catalytic converter.

This shield is clipped onto a round tube and then lightly secured in one corner with a screw.  The sheet metal is very flexible so the shield can move quite a bit, rotating on the clips.  Apparently I bumped it up towards the exhaust pipe while working under there recently.  Or perhaps the daughter drove over something that pushed it up.

At any rate, once I moved the shield down the rattle went away.

Shield pushed up nearly touches exhaust pipe.

Shield pushed up nearly touches exhaust pipe.  Rattles when engine rotates back.

Rotated shield down so that there is no metal contact.

Rotated shield down so that there is no metal contact.  No more rattle.

Get Rid of K&N Air Filter

November 30, 2014

On a side note to the previous post where we discussed how important the Mass Air Flow (MAF) sensor is, I want to bring up the topic of K&N brand air filters.

K&N makes a unique type of air filter that has a fine mesh screen that is saturated with oil.  The oil is supposed to trap dust and debris but also let more air flow through.  Some automotive enthusiasts swear by K&N because they reportedly increase engine horsepower.  Another benefit is that they can be cleaned and re-oiled so long-term cost is less than replacement filters.

In the case of these normally aspirated (non-turbo) 850 engines, there is no apparent increase in horsepower, at least in my experience.

The downside to the K&N filter is that because it is oiled, some of that oil will leave the filter and pass on to the intake manifold.  Immediately after the filter is the MAF sensor and it is reasonable to assume that some oil will end up on the sensor.  This would affect heat transfer and sensor accuracy.

With these two facts in mind, I opted to remove the K&N air filter from our 850 sedan and replace with a standard filter.

Removed and discarded K&N filter.

Removed and discarded K&N filter.

Installed new standard Wix filter.

Installed new standard Wix filter.

Air cleaner cover had alert stickers advising any service personnel that the air filter could be renewed instead of being replaced.

Air cleaner cover had alert stickers advising any service personnel that the air filter could be renewed instead of being replaced.

Removed K&N stickers from the air cleaner cover.

Removed K&N stickers from the air cleaner cover.

I welcome feedback in the comments from any readers who have more experience with K&N filters, pro or con.

#110 Preheat Air Valve Stuck, Affects MAF Sensor

November 30, 2014

Summary:  Mass air flow (MAF) sensor was misbehaving so it was cleaned along with sensor electrical connector contacts.  Also observed that the preheat air valve was stuck in preheat position so MAF was always seeing hot air.  Solved this problem by mechanically fixing defective air control valve in the position for fresh air only.

Details:  Along with the engine coolant temperature (ECT) sensor, the mass air flow (MAF) sensor is one of the two most critical sensors for Volvo 850 (and most other cars) engine operation.  Either being defective can cause the engine to run rough or not run at all and both affect fuel economy as well.

We had an incident a few weeks back where this project car was running very roughly.  I fiddled with the MAF sensor connector which is located next to the air cleaner housing and the engine started running smoothly again.  That told me there was an issue with the sensor or its electrical connection.

While the car was home this weekend I tore into the air cleaner to get to the MAF sensor and gave it a good cleaning.  Debris or dirt on the sensor elements can significantly affect the air flow reading and sometimes just a few taps will dislodge particles.  This may have been what happened when I wiggled the connector to restore smooth engine idle.

Cleaning of the MAF sensor is best done by removing the sensor from its housing.  However, on this car the screws from the factory require an unusual 5-point Torx security bit, which I don’t have.  Interestingly, our other 1997 model 850 has 6-point security screws which I can remove, so Volvo is inconsistent here.

This car had 5-point Torx security screw head and I don't have the tool for this.

This car had 5-point Torx security screw head for the MAF and I don’t have the tool for this…

...so I removed the whole MAF assembly for cleaning.

…so I removed the whole MAF assembly for cleaning.

So I sprayed MAF cleaner with the sensor still installed in the housing.  The sensor elements are very fragile and should never be touched or disturbed.  This is an expensive part to replace.

Cleaned MAF sensor with special spray.

Cleaned MAF sensor with special spray.  Other cleaners may leave residue which can harm or alter sensor reading.

Spray special MAF sensor cleaner on and around the sensor elements.

Spray MAF sensor cleaner on and around the sensor elements.

Make sure the laminar flow grid is also clean because air flows towards the sensor from this side.

Make sure the laminar flow grid is also clean because air flows towards the sensor from this side.

While I had the air intake and filter housing dissasembled, I checked the preheated air valve for proper operation.  This may be unique to North American 850s because of emissions requirements; I don’t know if this is a feature elsewhere.

There is a flapper valve under the air filter which selects between ambient air and preheated air (passes over exhaust manifold), or a mix of both, depending on air temperature.  On older 850s there is a thermostat that moves a rod to operate the air valve directly.  This is a known common failure item.  On late-model 850s and early V70s there is a thermostat in the air cleaner housing that modulates a vacuum valve to regulate the air valve in conjunction with a mechanical thermostat.

Access to the preheat air valve requires removal of air cleaner housing.

Access to the preheat air valve requires removal of air cleaner housing.  Valve can be seen hanging below the air cleaner

Preheated air valve is fastened to the air cleaner housing, on the right (bottom view).  Fresh air intake is at upper left, pre-heated intake far right.

Preheated air valve unclipped from air cleaner housing, on the right. Fresh air intake is at bottom, pre-heated intake far right, outlet at top.

On this car the air valve was stuck in the heated air position only, even with strong vacuum.  This means that the MAF sensor has been getting pre-heated air all the time.  The sensor reading will be affected by this and also may be damaged by constant flow of hot air.

Air valve always stuck in this position, blocking fresh air and open to pre-heated air.

Air valve always stuck in this position, blocking fresh air and open to pre-heated air.

Took apart the valve assembly to see if I could replace the thermostat and to get a better look at the vacuum valve part.  It gave me a good idea how it works but I quickly realized it was broken.

Preheat air valve disassembled.

Preheat air valve disassembled.

I applied a vacuum directly to the vacuum valve and could see the piston moving up and down as designed.

Piston extended with no vacuum.  Would select preheated air.

Piston extended with no vacuum. Would select preheated air.

Piston retracted with hard vacuum.  Would pull air valve to cold air inlet.

Piston retracted with hard vacuum. Would pull air valve to cold air inlet.

So the vacuum valve itself seems to be working but when the flapper is connected to the piston and the whole thing reassembled, it doesn’t move.  When I apply vacuum the piston does retract but the plastic connector to the flapper pulls around the thermostat and the flapper stays in preheat position.

Vacuum valve pulls piston down but plastic coupling stays up and valve stays in preheat position.

Vacuum valve pulls piston down but plastic coupling stays up and valve stays in preheat position.

There is clearly a different result when the flapper is attached.  I surmise that the plastic rim that pulls in was worn out and so it just slips around the thermostat when the vacuum valve pulls it in.  If the hole in the plastic were smaller it should pull the whole thermostat (metal rod) down as it does without the flapper attached.  So a proper fix would be to replace this vacuum valve assembly.

If this were the older preheat valve design it would be a simple part (thermostat) to swap out.  Unfortunately I can find no parts information on the vacuum-operated valve for this car (both of our 1997 850s have the late design).  It’s not mentioned in the usual parts places (FCP, IPD, Volvopartswebstore.)  The only mention of it is on the AllDataDIY site without parts info.

I suppose I could go to a Volvo dealer parts department and ask them to chase it down but we know how expensive that would be.  After reading the functional description of the design, I decided that we really don’t need the preheat feature here in central Texas where it rarely gets below freezing.  With 9-10 months of the year in a warm climate, the preheat valve should be open to cool air almost all the time, and there is no real consequence to not having preheated air.  So I rigged it to stay open to fresh air at all times, blocking the preheated air.

This was accomplished by drilling a hole in the flapper valve and using a long 2″ machine screw with a jam nut to keep it open.

Air valve held open to fresh air (closed to preheated air) with long screw and jam nut.

Air valve held open to fresh air (closed to preheated air) with long screw and jam nut.

In addition to preserving the life and functionality of the MAF, we hope to gain a little power out of this mod.  Other people with stuck air valves have reported an increase in power when they defeated the preheat intake.  I expect this is because the fresh air intake has a slightly larger cross-sectional area than the preheated hose so more air can get to the intake manifold.  Cooler air may also give a more accurate reading of air flow with the MAF as its principle of operation is to measure heat transfer in the sensor.  More accurate air flow measurement should give a better fuel/air ratio, resulting in more efficiency (better fuel economy?) and power.

Reassembled the air cleaner and reconnected everything else.  Also sprayed electrical contact cleaner on MAF sensor pins and sockets and mated/unmated a few times to wipe off oxide and prevent future intermittent connections.

Sprayed contact cleaner on both mating connector contacts to prevent future intermittents.

Sprayed contact cleaner on both mating connector contacts to prevent future intermittents.

??????????

Car runs fine now and time will tell how well the engine runs with this modification.

$0- no cost, using supplies and parts laying around.

Technical Notes:  The “new control method for preheating air” is described in the Technical Service Bulletin 2-25-818, excerpts given here:

The system controls the intake air temperature so that it remains between +27°C (81°F) and +37°C (99°F) in the 850.

Function

The intake manifold vacuum in the plastic tubes is distributed from the multi-nipple (1) via a bimetal sensor-controlled damper (2) to a vacuum tank (3) which controls a damper, which opens and lets hot air into the cold intake air. When the throttle is wide open no vacuum is created and the air damper remains closed.

When the outside temperature is cold and with wide open throttle (WOT), the center damper is held open by a wax thermostat (4), which is located between the vacuum tank and the center damper.

You can tell if the car has the new control scheme by the presence of two vacuum ports on the rear of the air cleaner cover.

Preheat air vacuum control thermostat on back of air cleaner cover with inlet and outlet tubing nipples shown.

Preheat air vacuum control thermostat on back of air cleaner cover with inlet and outlet tubing nipples shown.

Inside of air cleaner cover showing vacuum control thermostat.

Inside of air cleaner cover showing vacuum control thermostat.

Regarding the MAF, excerpts of the description and operation are given below:

The Mass Air Flow (MAF ) Sensor supplies the Engine Control Module (ECM ) with a signal describing the intake air mass.

This information is used to calculate:

Injection period

  • Ignition timing
  • If the engine coolant fan needs to run-on.

The mass air flow (MAF) sensor consists of a plastic housing containing a connector, electronic circuitry and an aluminum heat sink. The mass airflow (MAF) sensor measuring device is a heated film mounted in a pipe which is cooled by the intake air to the engine. The heated film consists of four resistors:

The mass air flow (MAF) sensor is supplied with battery voltage and has separate power and signal ground points. The signal from the sensor varies from 0 V to 5 V depending on the mass of air passing. Voltage increases with air flow.

Since working temperature is relatively high (170°C ), and the flow and temperature sensitive resistors are mounted on the side of the hot film, a burn-off function is not required.

The engine control module (ECM) will adopt substitute values if the mass air flow (MAF) sensor signal is missing or faulty.

The mass air flow (MAF) sensor is located between the Air Cleaner (ACL ) cover and the fresh air intake.

#109 Remote Keyless Entry Battery

November 30, 2014

One other complaint arrived with the car for the long weekend that involved the remote door lock/unlock feature that I retrofitted back in task #90.

When keyless entry was installed on this car it came with an old, used remote transmitter (key fob) with an aged battery inside.  Turns out the two coin cells inside were running low and the remote would work only in close proximity to the car.

Installed two fresh coin cells and now the remote transmitter works just fine.

Two things I learned while playing with the key fob:  First, the transmitter chirps once when the lock or unlock button is pressed and the batteries are fresh.  When the coin cells are low the key fob chirps three times when a button is pressed.  So that is one clue that the batteries need to be replaced.

Volvo 9442982 Key Fob

Transmitter chirps only once upon button push if batteries are fresh; more chirps indicates low battery charge.

The other thing I learned (actually, I knew this, but was reminded) is that lithium coin cells will test fine on a voltmeter even when they are fairly discharged.  Their chemistry still provides nearly full voltage with no load as when measured with a modern digital multimeter (DMM).

Battery charge is low even though both (2x3V lithium cell) read 6VDC with no load.

Battery charge is low even though both (2x3V lithium cell) read 6VDC with no load.

So to properly check the coin cells you need a special load tester to measure actual battery capacity.  Since few of us have such a thing, my suggestion is to listen to the key fob and replace batteries when you hear more than one chirp.

With fresh batteries the transmitter chirps only once and the doors can be locked/unlocked from a practical distance.

One other thought here on this topic– Sometimes the key fob transmitters go bad.  Even with fresh batteries they may not work.  If you suspect the remote is bad, you need to check for radio frequency (RF) signal being transmitted.  Some auto parts stores have a tester at the counter.  One other way to check at home is use your own RF sniffer.  I have this cheap one from Harbor Freight Tools that detects RF signals.  When you push the lock and unlock buttons, the tester will flicker and chirp to indicate a signal.

RF sniffer indicates that the remote is transmitting a signal when a button is pushed.

RF sniffer indicates that the remote is transmitting a signal when a button is pushed.

#108 Front Right Engine Mount

November 29, 2014

The car has come home from college for our Thanksgiving holiday and I got to work on a few things.

First up is the front right engine mount.  Daughter complained about vibration and I have replaced the other two engine pads already along with the upper and lower torque mounts so this is the last of the engine mounts to tackle.

The front right engine mount is the smallest of the three mounts and is located in the front right side of the car.  It is actually on the front left side of the transverse-mounted engine and is sometimes referred as front left.  At any rate, it is known to fail frequently and sooner than the others and it is the only one I have not replaced yet.  Visual exam showed no issues but I thought I should replace it based on time and mileage.

Starting point is with the front of the car lifted up securely on jackstands with the front right wheel off.  The wheel well flap is also folded back and secured to access the lower front of the engine.

Right front engine mount is visible just below and to the left of the crankshaft pulley (below red handle clamp).

Right front engine mount is visible just below and to the left of the crankshaft pulley (below red handle clamp).

Before removing the mount I measured the distance from the bottom of the oil pan to the top of the sub-frame for reference.  It was right around 3/8″ (9.5mm), just enough for me to stick my pinky finger in the gap.

Measured 3/8" gap between oil pan and sub-frame.

Measured 3/8″ gap between oil pan and sub-frame…

...which is just enough for me to stick my pinky finger in the gap.

…which is just enough for me to stick my pinky finger in the gap.

Removal of the mount involves unscrewing the two bolts to the engine (horizontal) and then two bolts to the sub-frame (vertical).  The three bolts on the right are easy to remove.  The one on the left requires swivel adapters and a short socket wrench to remove because it’s surrounded on all sides.

Two bolts to engine removed and two to sub-frame to free the mount.

Two bolts to engine removed and two to sub-frame to free the mount.

Once the engine mount is unbolted we lift the engine up slightly with a floor jack under the oil pan with a block of wood as a cushion and to spread the load around.

Lift engine off mount slightly.

The mount is now free to remove.

Old mount removed.

Old mount removed.

Compared old and new mounts and I was surprised to see that the old mount was actually in pretty good shape considering the car’s age.  Maybe it was replaced by previous owners; hard to believe this one is still going strong after 180K miles and 17 years.

Old mount was in pretty good condition.  Often the rubber tears out and the metal triangle collapses down, a sure sign of failure.

Old mount was in pretty good condition. Often the rubber tears out and the metal triangle collapses down, a sure sign of failure.

Old mount, top view.

Old mount, top view.

Old mount, bottom view.

Old mount, bottom view.

I could see some signs of the rubber tearing on the bottom which means it would eventually fail.  Since I had the new part I decided to be proactive and replace it anyway.

Now we slip the new mount in place (it has a keying feature to prevent installing backwards) and bolt to the sub-frame.

New mount bolted to sub-frame.

New mount bolted to sub-frame.

Then lower the engine back onto the new mount and then bolt the mount to the engine.

New mount bolted to engine.

New mount bolted to engine.

As expected the old mount was not seriously degraded so the new mount provided only a slight height increase.

New mount provides only a slight increase in gap since old mount was not badly worn.

New mount provides only a slight increase in gap since old mount was not badly worn.

Next we put the wheel back on, lower the car and tighten the wheel lug bolts and then run the engine to test for noise or vibration.  No problems.

$39.95 for a high-quality (Febi) after-market engine mount.

Sedan Drive Axle Broken

November 9, 2014

The white 850 sedan that I had been driving for 11 years has been sold to my oldest daughter so now the two girls both drive 850s.  I’m rocking a nice 2013 Honda Accord now.  I’m still caring for both 850s so they will still be featured in this blog.

The white sedan really let us down recently.  Daughter reported it making strange noises and vibrations so I drove it to see if anything obvious was wrong.  Sure enough, it made some horrible sounds accompanied by strong vibration and shuddering.  Then the car stopped moving altogether even though the engine was running fine.  No matter what gear I selected (this one has a manual transmission) the transaxle would not engage with the engine.  We managed to push it off the road and called for a tow truck to come haul it to the repair shop.

Car had to be towed (or more accurately, dragged onto a flat bed truck and driven) to an independent shop.

Car had to be towed (or more accurately, dragged onto a flat bed truck and driven) to an independent shop.

I just didn’t have the time or equipment to deal with this problem myself so we had it towed to an independent shop specializing in European cars.  I suspected the clutch was bad and that’s what the shop thought at first also.  But once they started disassembling the transaxle to get to the clutch they discovered that one of the driveshaft bearings was seized up or something like that.  Bottom line, one of the drive axles was broken and this caused the transaxle to not engage (something about differential gearing in there).  The clutch still had some life left in it, they reported.  So instead of a $1600 clutch job it turned out to be a $300 drive axle replacement.  The clutch will need to be replaced at some point in the future but we bought some more time with this one.  It’s back and running fine, although the shop found several things that needed attention.

#107 Windshield Wiper Arm, Round 2

October 21, 2014

The project car has been off to college since August so I haven’t posted anything lately.  It came back for a fall break visit with my daughter complaining about the driver side windshield wiper.  The arm was replaced early on with a generic part which was a mistake.  Even factory arms have a reputation for bending out of shape and then not making complete contact with the windshield and generic parts fail faster.

Much of the left side was not wiped.

Much of the left side was not wiped.

Hard to tell from these photos but the blade doesn’t make good contact on the left side of the windshield and this is a problem for the driver when needed.  You can see how much I had to bend the arm to make even moderate contact and this is as much as I could improve it.

Even with arm bent a ridiculous amount the wiper blade wasn't working well.

Even with arm bent a ridiculous amount the wiper blade wasn’t working well.

I even tried the suggested tricks to shave off some metal down at the base to allow the spring to pull the arm in tighter but that accomplished very little.  The real problem here is the cheap substitute arm that I used the first time; it is weaker than the factory parts marked Bosch.

Because this is an important safety issue and because I already wasted money on a cheaper part, I bought an expensive factory part from the local Volvo dealer.  Replaced it and now it wipes tight against the windshield like it should.

Genuine ($$$) arm has Volvo part number stamped on it.

Genuine ($$$) arm has Volvo part number stamped on it.

Genuine arm is also stamped Bosch and probably made in Belgium.

Genuine arm is also stamped Bosch and probably made in Belgium.

Wiper properly clears the windshield with new arm.

Wiper properly clears the windshield with new arm.

$66 for factory wiper arm LH

Gas Shock Failure Reference Video

August 31, 2014

The Volvo 850 has a number of gas-charged shocks on it.  Primarily the rear suspension shock absorbers and gas shocks as part of the strut assemblies on the front suspension.  Suspension shocks allow linear movement with some resistance  where they dampen natural oscillations.

I wanted to share this outstanding video explaining how gas shocks operate and how they fail over time.  Particularly interesting is the multi-stage valves inside that respond to the force of different events:

How Shocks & Struts Wear

I’m not trying to push a product, just acknowledging that the industry guidance for changing shocks and struts at 50K-60K mile intervals has some validity.  By the time shocks or struts are visibly or obviously bad the shock is way past needing replacement and you would have experienced a big improvement in ride comfort, tire wear and handling if they were changed sooner.

Manual (non-electric) front seats and the wagon tailgate also have gas shocks, or, more appropriately, gas springs for lift support and I changed these in previous posts.  They are less prone to constant vibration so they don’t have the same failure mode but the general principle of a gas-filled cylinder still applies.  Over time and use the gas (usually nitrogen [N2]) will leak out and they lose their force to push the rod out and do the job.  At this point they need to be replaced.

#106 Strut Replacement

August 3, 2014

Struts were replaced, giving a huge improvement in ride, noise and turning smoothness.

Besides making squeaking noises and a less-than-comfortable ride, the struts needed replacement because the spring seat on the right side was failing.  The rubber seat where the top of the strut spring sits is a well-known failure item on Volvo 850s.  If you take a wrench to the upper nut and turn it, there should be little movement on a good seat and it should quickly snap back to the relaxed position.  You can get quite a bit of twisting movement on spring seats that are failing and the nut spins freely when they are torn completely.  The nut could twist quite a bit on this car so needed a seat replacement along with the gas shocks and who knows what else in these strut assemblies.

If you can get any real movement out of these nuts at top of strut, the rubber spring seat is failing.

If you can get any real movement out of these nuts at top of strut, the rubber spring seat is failing.

Struts should always be replaced in pairs to give equal ride on both sides, even if only one is bad.  In this case the right side strut had a torn spring seat while the left side was rather squeaky.  Both really did need replacement.

Started by lifting the front of the car securely on jackstands with the wheels removed.

Strut replacement begins with car on stands and wheels off.

Strut replacement begins with car on stands and wheels off.

Next is to support the wheel hub with a jack to just take a little load off the strut.

Support the wheel hub so the shock is not extended.

Support the wheel hub so the shock is not extended.

To free the strut for removal involves unscrewing six fasteners in three locations.  First unbolt the sway bar link from the  strut mount (one nut).

Sway bar link disconnected from strut.

Sway bar link disconnected from strut.

Then unbolt the lower strut from the steering knuckle of the wheel hub (two bolts/nuts).

Strut unbolted from steering knuckle (wheel hub).

Strut unbolted from steering knuckle (wheel hub).

Finally unscrew the nuts securing the upper strut bearing mount under the hood (three nuts).

Top of strut (bearing plate) unbolted from under hood allows the strut to drop.

Top of strut (bearing plate) unbolted from under hood allows the strut to drop.

There is also an anti-lock brake (ABS) sensor cable grommet that needs to be pulled out of the bracket on the strut.

ABS sensor cable pulled out from bracket.

ABS sensor cable pulled out from bracket.

The actual sequence here is not important but all four things need to happen to free the strut from the car.  Now that it’s free, the support can be removed and the strut can simply be dropped down and removed from under the wheel well.  The old struts (not original, but not sure when they were last replaced) were very grimy, worn and torn up.

Struts in bad shape.

Struts in bad shape.

At this point the strut is typically disassembled with special tools and then reassembled with new parts as needed.  The spring is almost always salvaged and the other parts may be replaced depending on condition.  It’s generally a good idea to replace everything but the spring.

For this job, however, and this is where many Volvo purists will get upset, I did not rebuild the struts.  Instead I bought complete strut assemblies ready to go.  This gives us new gas shocks, coil springs, dust boot, bumper, bump stop, spring seat, bearing plate, retaining nut, upper cushion and top nut.  The quality of each of these may not be factory level but I’ll be happy if we get five years out of these.  I used Gabriel ReadyMount complete strut assemblies (G57040).  Three factors in choosing these: 1) Price was unbeatable with the pair running only $250 after instant rebate; 2) Time saved not rebuilding the struts; this cuts my effort down by at least three hours per car; 3) Favorable reports about these struts by certified buyers on their 850s.  Volvo forums lean towards factory only parts, or at least high quality after-market level.  I have no way of knowing where these complete assemblies fit in to this mix so this is something of an experiment.  I will update this post if and when there is an issue with the struts.

Comparing the old and new strut assemblies is very favorable.  The only missing detail is the ABS sensor wire bracket which needs to be screwed onto the appropriate side.

Complete strut assembly matches original perfectly.

Complete strut assembly matches original perfectly.

??????????

Installation of the new strut assembly is straight-forward; just reverse the removal procedure.  Orientation of the strut is impossible to confuse as both top and bottom have to be turned a certain way to install.  The upper mounting is easy but the lower connection to the steering knuckle takes some effort to line up the bolt holes.  As long as you can move the wheel hub around it can be done.

Secure upper part of strut loosely with nuts.

Secure upper part of strut loosely with nuts.

Strut roughly fastened at top.

Strut roughly fastened at top.

Strut roughly fastened at top.

Strut roughly fastened at bottom.

One extra detail is to screw the ABS sensor cable bracket into the appropriate side.  The strut has holes pre-drilled for this and self-tapping screws are provided.

Screwing in ABS sensor cable bracket is easy.

Screwing in ABS sensor cable bracket is easy.

Now it’s just tighten all the fasteners to the factory torque spec.  Again, in no special order:

Lower strut secured to steering knuckle.

Lower strut secured to steering knuckle.

New fasteners are recommended for the lower strut bolts but I didn’t order any so just re-used the old ones.

Sway bar link to strut nut.

Sway bar link to strut nut.

Slip ABS sensor wire grommet into bracket.  This takes a bit of force.

Slip ABS sensor wire grommet into bracket. This takes a bit of forceful massaging.

Upper mounting nuts.

Upper mounting nuts.

Once everything is replaced and secure on both sides, just put the wheels back on and lower the car and make a test drive.  Listen for any unusual sounds and feel how the front of the car rides and steers.  For this task the ride was much improved; all the squeaking and popping was eliminated and the turning was smoother.  I attribute much of the improved feel to the new springs which give more support than the originals with 17 years of compression on them.

New struts require front end alignment check and adjustment as needed because they alter the geometry of the front wheels, thus affecting caster, camber and toe.  Fortunately we purchased lifetime alignment at Firestone so I’ll bring the car in for free alignment shortly.

I dissected one of the struts to see how bad it was and present a short photo essay below.

You need some kind of convenient and sturdy work platform.

You need some kind of convenient and sturdy work platform.

Top nut and cushion washer can be removed at any time; these are not under spring compression.

Top nut and cushion washer can be removed at any time; these are not under spring compression.

To disassemble the strut further, you must compress the spring to relieve tension.  These two-piece screw compressors are most common but the cheap ones are scary fragile.

To disassemble the strut further, you must compress the spring to relieve axial force. These two-piece compressors are most common but the cheap ones are scary fragile.

Alternative spring compressor is this massive monster that is sturdy but gets in the way.

Alternative spring compressor is this massive monster that is sturdy but awkward.

??????????

I like the sturdiness of the big red one but it doesn’t clamp the coils as neatly as the two-piece compressor which is less likely to damage the finish (and let the coil rust).  So the two-piece ones are probably better for these smaller coils (compared to larger vehicle springs).  Just keep a close eye on them in case they show any signs of breaking.

With spring compressed the retaining nut can be removed.  This takes a special star-shaped tool and another tool to hold the gas cylinder shaft from spinning.

With spring compressed the retaining nut can be removed. This takes a special star-shaped tool and another tool to hold the gas cylinder shaft from spinning.

Retainer nut removed.

Retainer nut removed.

Bearing plate pulled out from rubber spring seat nipple.  They may have to be pried apart.

Bearing plate pulled out from rubber spring seat nipple. They may have to be pried apart.

Bearing plate in fair shape but bearings were a little rough and worn.

Bearing plate in fair shape but bearings were a little rough and worn.  Rough bearing reduces steering smoothness.

Spring seat, the weakest link in the whole strut assembly.  Many folks recommend using a more sturdy part from the XC90 which fits the 850.

Spring seat, the weakest link in the whole strut assembly. Many folks recommend using a more sturdy part from the XC90 which fits the 850.

You can see the rubber torn in a ring around the shaft on top...

You can see the rubber torn in a ring around the shaft sleeve on top…

...and bottom.

…and bottom.

Bump stop almost disintegrated.

Bump stop almost disintegrated.

??????????

Shaft protective boot badly torn which lets dirt get into gas cylinder seal and make it slide roughly.

Shaft protective boot badly torn which lets dirt get into gas cylinder seal and make it slide roughly.

With gas cylinder removed all that's left is a compressed spring.

With gas shock removed all that’s left is a compressed spring.

At this point if you were rebuilding the strut you would put in a new gas shock and replace any other worn parts as it is re-assembled in reverse order.  There is a starting compression length for the spring that pre-loads the force when you tighten the retaining star nut.

Spring compression length spec when reassembling strut.

Spring compression length spec when reassembling strut.

It’s also important to observe correct placement of the spring ends at top and bottom on the gas shock and spring seat, respectively.

$250 for two Gabriel ReadyMount complete strut assemblies on Amazon

Technical Notes:  Strut assemblies are the primary front end suspension components.  The coil spring around the gas cylinder provides the actual suspension of the chassis to the ground while the gas shock absorber provides dampening of the up/down motion for comfort and control.  Unlike the rear suspension which has separate shocks and coil springs, these are integrated for minimal use of space.  They need to rotate with the wheels when turning so there is a bearing at the top which allows for the struts to pivot with the wheels.

#105 Rear Engine Pad/Vibration in Drive With Brakes On

August 3, 2014

Finally solved that nuisance issue with the car vibrating/rumbling heavily when the car is in drive with the brakes on.  Replacing the rear engine pad was the trick.  Until now whenever the car was in neutral/park or reverse, there was minimal vibration felt in the driver’s seat.  However, when in drive with the brakes applied, the car would really rumble and vibrate strongly.  This problem is unique to the automatic transaxle where the idle torque of the engine is dissipated by the brakes.  When the brakes were released, the rumbling would stop.

I zeroed in on the rear engine pad by observing the engine rotation when I had the upper torque mount bolt removed to allow it to move freely.  In neutral or park the engine is centered on the upper torque bolt.

Upper torque bolt centered when...

Upper torque bolt centered when…

...the transmission is in neutral/park.

…the transmission is in neutral/park.

In reverse the engine wants to twist towards the front of the car, applying pressure on the front engine mount/pad.

Engine twists to front when in reverse.

Engine twists to front when in reverse.

In drive the engine wants to twist to the rear, applying pressure on the rear engine mount/pad.

Engine twists to rear when in drive.

Engine twists to rear when in drive.

Observing this it is apparent that the rumbling in drive only must be related to the rear engine mount so I replaced the rear engine pad (left side of transverse-mounted engine).  This made a huge difference and I was not surprised at the results when I saw the old pad and installed the new one.

Started replacement by unbolting two items from above before the car was lifted.  First is the upper torque mount.  Unbolting this allows the engine to move up on the left side of the car, just above the rear engine pad.

Upper torque mount unbolted.

Upper torque mount unbolted.

Next is the upper nut fixing the rear pad to the engine.  It’s deep under the hood so a long socket wrench wobble extension really helps, as does removing the air pre-heat flex pipe for more direct access.  It can be done with a shorter socket working underneath all that but you need long arms and some dexterity.

Upper rear engine pad nut removed.

Upper rear engine pad nut removed.

For this it helps to have a long socket wrench extension and to remove the air pre-heat pipe.

For this it helps to have a long socket wrench extension and to remove the air pre-heat pipe.

Now the front of the car needs to be lifted securely onto jackstands.

Front of car lifted onto jackstands with rear wheels blocked.

Front of car lifted onto jackstands with rear wheels blocked.

Three things need to be unbolted with the front lifted.  First the lower torque mount to the automatic transaxle.  This allows the left side of the engine to lift up.

Lower torque mount unbolted from sub-frame so engine can move up.

Lower torque mount unbolted from sub-frame so engine can move up.

Second the bolt securing the rear engine pad to the frame.  This is recessed so you need a socket wrench extension run between the frame and drive axle.

Rear engine pad unbolted from below.

Rear engine pad unbolted from below.

Long socket wrench with wobble extension needed to unbolt engine pad from below between sub-frame and drive axle.

Long socket wrench with wobble extension needed to unbolt engine pad from below between sub-frame and drive axle.

Finally unbolt the engine from its left mount to allow freedom of movement at the rear of the engine.  This is not in the factory instructions or in the Haynes manual but I found it to be necessary to get enough movement of the engine.  Others on the internet also mention this requirement.  For this the right front wheel needs to be removed and the plastic flap lifted up for access.

Right side engine mount unbolted (two screws just below to the left of main pulley).

Right side engine mount unbolted (two screws just below and left of main pulley).

Now that everything is freed up we need just lift the left rear corner of the engine to remove the old pad and install the new one.

Old (probably original) pad unbolted top and bottom, ready to pull out.

Old (probably original) pad unbolted top and bottom, ready to pull out.

Service manuals indicate 30mm maximum lift to avoid damaging the inner tie rod ends so I took a reference measurement of the bottom of the engine (actually, transmission body bolted to the engine) to a point on the sub-frame.  I measured about 10mm.

Engine lifting reference measurement about 10mm.

Engine lifting reference measurement about 10mm.

For lifting I used a floor jack with a block of wood to spread the load and cushion it.  I got just under 30mm of lift before it started lifting the car, indicating that I had maxed out engine movement.

Lifted left rear corner of engine nearest pad.

Lifted left rear corner of engine nearest pad.

The rear pad was now free to move so I pulled it out for inspection.

With engine lifted pad was now free.

With engine lifted pad was now free.

Empty space where pad was located.

Empty space where pad was located.

The pad fell into three pieces when I removed it.  The lower metal mount had separated from the rubber cushion and the safety wire came off.  Comparing old and new mounts, the original was significantly shorter and somewhat softer than the new one.

Side-by-side comparison of old and new pads.

Side-by-side comparison of old and new pads.

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You can see how much length was lost in the old pad in the tapered section.

I used an after-market pad for about half the price of a factory part.  I’m not concerned about getting another 10 years life out of this car and I’m trying to be economical.

When installing the new pad, there is an orientation to be observed.  The triangular pin needs to fit into the offset hole near the upper bolt hole.

Triangular pin must locate in this...

Triangular pin must locate in this…

...mating hole offset the axis to provide pad orientation.

…mating hole offset the axis to provide pad orientation.

It took a little bit of fussing and twisting to get the new pad installed but did not require forceful prying.  Guess I had just enough lift to slip the new pad in.

New pad in position, ready to lower engine.

New pad in position, ready to lower engine.

The engine was lowered and as expected, the resting height was now greater with the new pad.  The old pad had collapsed by the 9mm measured difference.

Engine lowered and resting on new pad.

Engine lowered and resting on new pad.

About 19mm clearance now with new pad.  Old pad had collapsed 9mm over time.

About 19mm clearance now with new pad. Old pad had collapsed 9mm over time.

Now all we have to do is fasten everything back together again and torque to specification.  Right engine mount bolts, rear pad lower bolt, lower torque mount nuts and then wheel back on right front.

Right engine mount bolts secured.

Right engine mount bolts secured.

Lower rear pad bolt secured.

Lower rear pad bolt secured.

Lower torque mount nuts secured.

Lower torque mount nuts secured.

Lower the car off the jackstands and then secure the rear pad upper nut, pre-heat pipe and upper torque mount.

Upper rear pad nut secured.

Upper rear pad nut secured.

Upper torque mount bolts secured.

Upper torque mount bolts secured.

At this point I was not surprised but was very pleased to confirm that the strong rumble and vibration was gone when the car was in drive and the brakes were applied.  This one has been bugging me since we got the car a year and half ago but has never been my highest priority.

I suspect that the rear engine pads in automatic transaxle cars driven mostly around town get a lot more wear and will fail sooner than manual transmission cars because there is so much more force and wear on that pad from all the idling in stop and go traffic.

 $54.87 for new after-market engine pad.

#104 Muffler Replacement

July 16, 2014

Oh, well– that muffler patch didn’t hold.  A couple of the larger holes blistered out their patches and there is at least one small hole again, so now we need to replace the muffler.  As mentioned in post #101, exhaust leaks are a safety concern with the potential for deadly carbon monoxide gas building up in the cabin.

This is a long and detailed post.  If you’re interested in the topic, read on.  Otherwise, here is the…

Summary:  Previous attempt to patch muffler holes failed.  Removed old muffler assembly (large muffler, long inlet and outlet pipes).  Installed replacement assembly.  Original exhaust tip/tail pipe was coming apart so I rigged it up temporarily while waiting for a new end pipe.

Details:  In researching a muffler replacement I learned a few interesting things.  First, it is unusual for Volvo mufflers to fail, unlike most other cars.  The factory mufflers are made of steel and coated with aluminum (aluminized steel) for corrosion resistance.  I read on the internet that Volvo has a lifetime warranty on their mufflers, but after checking with the dealer service shop this does not apply to North America, if it does anywhere, so that may be an internet legend.  One local independent Volvo shop doesn’t stock mufflers because he never sees them fail and would have to special order the part.  We surmise that this car was exposed to salty ocean air somewhere in its life because it came from coastal California originally and when we bought it there was a Texas beach parking sticker on the windshield.  I suppose in colder climates where the roads are salted for ice they see more exhaust failures, or, more likely, the cars rust out faster and are scrapped at a younger age.

Second, this car has a large and unusually-shaped muffler and none of the exhaust repair places have a generic replacement, so we’re stuck buying a factory muffler or an exact-fit after-market unit.

Third, the muffler comes with long pipes permanently welded at inlet and outlet, so it’s more than just a muffler; there are also several feet of exhaust tubing.  The whole assembly is about seven feet (2.1m) long.

The good news is that there is only one simple clamped connection aft of the catalytic converter directly below the hand brake lever.  The rest of the muffler/pipe assembly just hangs under the car.  So replacement is fairly straight-forward but it’s not physically easy.

For a replacement I hesitated at the price tag of a factory muffler assembly.  The best price I could find on the only valid part number that a Volvo dealer shop gave me (31372150) is about $400.   Add an hour of labor if I paid someone to do the work, plus any other parts that may need to be replaced.

So I decided to do the work myself and buy a quality after-market muffler assembly.  I chose a direct-fit Bosal unit, part number 290-517 for under $200.  The unit fits exactly and the quality and workmanship are close to Volvo OEM.  At any rate, even if it doesn’t hold up as long as the original one, I doubt that this car will be around another 17 years.

The biggest surprise with the new muffler is that the supplier just slapped shipping labels on it and sent it via FedEx.  Showed up on our porch with no box or packaging.

New muffler assembly arrived with no packaging; just as shown here.

New muffler assembly arrived with no packaging; just as shown here.

At least they wrapped some protection around the pipe ends and it is in good shape.  I guess these mufflers are pretty robust and don’t need much packaging.  The supplier claims this is standard procedure.

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To start the replacement, I removed the end pipe from the exhaust tube while it was still on the car to reduce the weight by a couple of pounds.  With the exhaust still on the car another advantage is that the tube is fairly stable for wrestling the rusted end pipe off.

End pipe before removal.

End pipe before removal.

End pipe before removal.  Fixing bolt removed.

End pipe before removal. Fixing bolt removed.

The end pipe was also pretty well stuck on the exhaust tube so I had to break it loose with a hammer and wood block, then rock and twist it off.

End pipe removed.

End pipe removed.

End pipe removed.

End pipe removed.

Unfortunately the fixing screw was corroded solid so the nut just pulled out of the end pipe.

End pipe fixing bolt chemically welded to press nut just pulled through the pipe.

End pipe fixing bolt was fused to press nut so it pulled through the corroded pipe when I tried to unscrew it.

End pipe before removing corroded bolt.  It's pretty corroded just at the seam.

End pipe before removing corroded bolt. It’s pretty corroded just at the seam.

To replace the muffler assembly I lifted the the car and set on jack stands as high as practical to get plenty of working room under there.

Lifted the car and rested on jack stands.

Lifted the car and rested on jack stands.

Then I unbolted the exhaust coupling beneath the driver’s seat.  This took some effort as the bolts were rusty with years of heat working.  I gave them a good shot of penetrating oil (PB Blaster) days in advance and another dose before trying to unbolt the clamp.

Sprayed penetrating solvent onto clamp bolts days in advance to help loosen them up.

Sprayed penetrating solvent onto clamp bolts days in advance to help loosen them up.

I did this first because it was the big unknown that might cause lots of trouble or even make me resort to taking the car to a shop.  Fortunately a socket wrench with long arm did break the bolts free so I was pleasantly surprised that it went easy and well.  The clamp and fasteners were in much better shape than they appeared.

Once the bolts are loose, the nut on top will spin free.  Need a short socket to hold the nut.

Once the bolts are loose, the nut on top will spin free. Need a short socket to hold the nut.

Clamp removed. Joint still stuck together rather solid.

Clamp removed. Joint still stuck together rather solid.

Now that the exhaust pipe was unclamped I unhooked each of the exhaust hangers, starting with the muffler.

Released muffler hangers both sides.

Released muffler hangers both sides.

Moving to the back with the two hangers near the end of the tail pipe.  Note the muffler and tailpipe hangers are slightly different parts.

A shot of silicone lube really helps the hangers slide off the chassis hooks.

A shot of silicone lube really helps the hangers slide off the chassis hooks.

Tailpipe hangers  released.

Tailpipe hangers released.

With all four hangers loose the whole exhaust is free and rests on the rear suspension arm.

With all four hangers loose the whole exhaust is free and rests on the rear suspension arm.

Now we need to break the corrosion weld in the front joint so the whole assembly is loose.  For this the easiest thing was to grab hold of the muffler and twist along the axis.  The unclamped joint to the catalytic converter broke free easily this way and the whole assembly could now be removed.

Coupling freed up by twisting muffler.

Coupling freed up by twisting muffler.

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Before pulling the muffler out I removed the rubber hangers so they wouldn’t get damaged or snag on the chassis.

Removed rubber hangers so they wouldn't get damaged or snag the chassis while pulling the muffler out.

Rubber hangers removed.

The whole muffler assembly weighs about 30 pounds (13.6kg) so it’s not too heavy to handle under there.  Having a helper is best but I was able to muscle the thing around.  Because of the way it fits under the car, the muffler assembly must be pushed towards the front of the car to remove it to clear the rear suspension arms.

Now comes the trickiest part of the whole process.  The tail pipe has to snake over the rear suspension arms and through a small area between the fuel tank and the rear spring.  The tail hanger hooks really stick out so the whole assembly has to twist around at different angles while drawing the muffler forward.  For this to happen you need a fair bit of clearance between the muffler and the ground.  I was right at the edge for height with my jackstands.  The muffler hooks really scraped the driveway but I managed to pull it out.

Pulling the assembly forward requires a lot of pulling and twisting; need ample ground clearance.

Pulling the assembly forward requires a lot of pulling and twisting; need ample ground clearance.

Old and new muffler assemblies are very similar.  Minor difference in hanger hooks and muffler shape, none of which affect fit.  Dimensions are very close but I didn’t measure anything.

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New muffler on hood for size reference.

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New muffler has some dark spots but those are not rust; it’s heat discoloration from welding.

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Only with the muffler removed could I see that the top was also rusted out with leaky holes.  So it’s good that we replaced it, even if the patch had held.

Old muffler had leaks on top as well.  Couldn't be seen until it was removed.

Old muffler had leaks on top as well. Couldn’t be seen until it was removed.

The new exhaust gets installed in the reverse manner. First we have to roll the tail end in over the rear suspension arms.  Once again this involves a lot of pushing, pulling and twisting.

New muffler being routed over rear suspension arms.

New muffler being routed over rear suspension arms.  Wrapping left on to protect ends.

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New muffler twisted into rough tail position.

New muffler twisted into rough tail position.

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Now we can unwrap the protective plastic and carboard from both ends.

Protective packaging removed from both ends.

Protective packaging removed from both ends.

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Time to couple the front pipe to the outlet of the catalytic converter.  The connection is sort of a shallow ball and socket joint.  No gasket, just the two pipes cupped together.

New muffler inlet pipe connected to engine exhaust.  Simple ball and socket coupling.

New muffler inlet pipe loosely connected to engine exhaust. Simple ball and socket coupling.

Before clamping the joint we need to position the muffler in its approximate location so things are stable and in place.  Used the car lifting jack to support the muffler.

Supported muffler with jack to keep joint in place.

Supported muffler with jack to keep joint in place.

Also cleaned up the original clamp parts with solvent and a wire brush.

Cleaned up original clamps and fasteners.

Cleaned up original clamps and fasteners.

Secured clamp over joint and tightened it.  I pulled hard towards the back to make sure it didn’t separate.

Clamped joint with original parts.

Clamped joint with original parts.

Now it’s time to start hanging the muffler and tail pipe.  Slipped the rubber hangers over each hook on the exhaust.  It is easier to hang with the rubber hangers attached to the exhaust than it is to slip the exhaust into the hangers already in place.  One of the rubber hangers was really cracked and coming apart so I replaced it with a new part.  Then lifted the muffler and/or pipe and positioned the hanger on each chassis hook one -by-one.

Replaced one bad hanger with a new part.

Replaced one bad hanger with a new part.

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Once again, silicone lube really helps the hooks slide into place.

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There, we’re done with the muffler assembly.  I ran the engine to check for leaks while the car was still on stands.  No apparent leaks and it sounds just like a typical 850 exhaust note– good news!  Took a couple of hours so far

But we’re not quite done and the rest took most of the afternoon.  The exhaust tip or tail pipe is called the end pipe by Volvo.  This is the last 11 inches of pipe that connect to the end of the muffler outlet pipe and through the cutout in the bumper.  I removed the original one way back at the beginning and as mentioned it was broken.  Turns out things were even worst because a big part of it–a internal tubing sleeve–was fused to the old exhaust pipe.  So we need a replacement.

End pipe not only lost its fixing screw but the inner sleeve was stuck to the old exhaust tube.

End pipe not only lost its fixing screw but the inner sleeve was stuck to the old exhaust tube.

Unfortunately it’s not a stock part at the Volvo dealers and they want $55 for one with one week leadtime.  After-market tailpipes run about $40 but none are stocked anywhere in town.  So I ordered an aftermarket part to be delivered next week and rigged up the old one to be temporarily functional.  Ugly but secure.  Just not good long-term.

Played around with various techniques and a visit to two hardware stores before I finally found something that worked, more or less.  Basically added a pair of new fixing bolts to clamp the tail pipe to the exhaust tube.

Drilled a couple of holes near the original fixing bolt hole.

Drilled a couple of holes near the original fixing bolt hole.

Ran a pair of bolts through the holes held captive by two nuts inside.

Ran a pair of bolts through the holes held captive by two nuts inside.

Shoved the end pipe over the exhaust as far as the nuts would let it go, then tightened the bolts against the tube to secure.  Nuts want to spin so a screwdriver was used as a wedge.

Shoved the end pipe over the exhaust as far as the nuts would let it go, then tightened the bolts against the tube to secure. Nuts want to spin so a screwdriver was used as a wedge.

Temporary end pipe looks OK and is functional.

Temporary end pipe looks OK and is functional.

Shoved a mass of steel wool into gap between end pipe and exhaust tube to minimize gases forward.

Shoved a mass of steel wool into gap between end pipe and exhaust tube to minimize gases forward.

There, it’s all in and ready to roll.  Sounds good now and no more concern about exhaust leaks.  Test drive OK except it reminded me that I should have removed all the labeling from the muffler and tubing.  I had removed what I could but some labels were really stuck on so I just gave up.  Unfortunately they got very smelly with some smoke after the exhaust heated up.  So next time (if there is one) I will go to the effort of removing all labels.

Couldn't get these labels off easily so they started removing themselves in a smoky, smelly manner.

Couldn’t get these labels off easily so they started removing themselves in a smoky, smelly manner after the pipe heated up.

Update 7/27/14: Removed temporary end pipe and replaced with high-quality after-market exhaust tip.

Used a Walker 41827 end pipe, which was much cheaper than the factory part and it fits just fine.  Note that the wagon part is slightly longer than the sedan pipe, which is a different part number (both Volvo and Walker).

Started by removing the label (see, I learn from my mistakes!) with xylene solvent and a putty knife, then wiping off with towels and finished with all-purpose cleaner and towel dry.

Used solvent to soften label, then scraped label off and wiped remaining residue off.

Used solvent to soften label, then scraped label off and wiped remaining residue off.

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Comparing factory pipe (R) to new Walker pipe (L), you can see the after-market pipe is tapered to fit the exhaust where the factory part had a sleeve inserted in the end beneath the fixing bolt.

New pipe necks down to fit over exhaust tube where factory pipe had an internal sleeve.

New pipe necks down to fit over exhaust tube where factory pipe had an internal sleeve.

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Slid the new pipe over the end of the exhaust just past where it necks down and tightened the fixing bolt.  I chose to rotate the pipe where the bolt was parallel to the ground.

Bolt turned parallel to ground.

Bolt turned parallel to ground.

Tightened fixing bolt on exhaust pipe before it necks down.

Tightened fixing bolt on exhaust pipe before it necks down.

Positioned just right.

Positioned just right.

Looks great now with the new end pipe.

$197 for a mail-order muffler with free shipping and no sales tax (and no packaging!) +$40.90 for end pipe = $238 total.

#103 Replace Radio Lights

July 13, 2014

Half of the lights on the Volvo factory radio have been out since we bought the car.  It was hard to see the radio buttons and controls in the dark without them.

Several lamps out on the radio so driver can't see buttons on the right side after dark.

Two lamps out so driver can’t see buttons on the right side after dark.

I think this is a safety issue since at night the driver’s eyes spend more time trying to see and figure out all the invisible radio buttons and less time on the road.  So I should have made this a higher priority.

Anyway, this is a relatively simple fix and rather low cost.  There are two good on-line turorials for this and I recommend them both:

http://www.atthetipwebs.com/technologyinstructions/radio_volvo.htm

http://www.matthewsvolvosite.com/volvo-radio-light-bulb-replacement.html

Neither applied 100% to my experience but they both cover the basics.  Mainly because these writeups cover the CD version SC-815/6 and this car had the cassette tape feature, SC-710.

Getting the factory radio out of the car is really simple.  Just push in the two rectangular tabs which will then pop out to create finger pulls.  The radio is pulled out using these handles.

Push in tabs to release radio with finger pulls.

Push in tabs to release radio with finger pulls.

Radio pulled out most of the way.

Radio pulled out most of the way.

Before unplugging power make sure you have the radio security code written down somewhere so you can use it again.  Unplug the radio cable by pulling straight back and push the release button to unlatch the rectangular connectors before pulling them out.

Radio uplugged.

Radio uplugged.

Take the radio to a bench or table with appropriate padding to disassemble.

Radio ready for disassembly.

Radio ready for disassembly.

First you pull the volume knob and tone slider knobs off and set aside (no tools needed).

Volume control knob and three slider knobs pulled off.

Volume control knob and three slider knobs pulled off.

Next you have to get the front bezel off.  A couple of screws need to be removed on each side (maybe more with SC-81X).

Two screws on both sides need to be removed.

Two screws on both sides need to be removed.

Now you need to simultaneously release six plastic tabs while pulling the bezel forward.  This isn’t easy so it helps to release the four on top and bottom and wedge something under the tab (such as a toothpick) to keep them released.  Then release the two on the sides and you can pull the bezel off.

Pry up on four top/bottom tabs...

Pry up on four top/bottom tabs…

...and wedge something under each one to keep it unlocked.

…and wedge something under each one to keep it unlocked.

Pry up on both side tabs to release bezel.

Pry up on both side tabs to release bezel.

With the bezel off you can see the printed circuit board (PCB) which contains the pushbuttons and lights.

With front panel (bezel) off you can see the PCB underneath.

With front panel (bezel) off you can see the PCB underneath.

Light pipes on back of faceplate/bezel direct lamp light to individual buttons.

Light pipes on back of faceplate/bezel direct lamp light to individual buttons.

PCB has pushbuttons (red) and backlight lamps (blue), plus slider controls and LCD display.

PCB has pushbuttons (red) and backlight lamps (blue), plus slider controls and LCD display.

Now you need to remove the PCB to get underneath it to remove/replace lamps.

Remove three screws to release PCB.

Remove three screws to release PCB.

With this cassette model there are three screws holding it in place.  With the CD version there are twist tabs that secure the board.

Now just lift the board up/out by gently prying and wiggling.  The lamps are screwed into the PCB from behind.

Back side of PCB showing lamp sockets (black).

Back side of PCB showing lamp sockets (black).

Since we’re going to this much trouble, we will replace all the lamps, even those which are still working.  They are likely to fail soon anyway.  This way they are all the same age and brightness.

This cassette version has six lamps while the CD version seems to have only five.

1/8 turn CCW loosens lamp from PCB so it can be pulled out from behind.

1/8 turn CCW loosens lamp from PCB so it can be pulled out from behind.

All six lamps removed from board.  You can see the holes where they were installed.

All six lamps removed from board. You can see the holes where they were installed.

The lamps have a blue filter sock over them to diffuse the light and give it a cool color.  Need to remove these blue booties and transfer them to the new lamps.

Carefully twisted and pulled the blue boots off the old lamps.

Carefully twisted and pulled the blue boots off the old lamps.

Replacement lamps from Honda (part number 35505-S84-N01.  Gray plastic base is different but color is not important.

On my 850 sedan I used JKL part number CNW1-23 which works fairly well.  You can also get the blue boots, JKL 39-02-5A.  Both of these can be purchased from Mouser electronics.

Honda replacment lamps work perfectly.

Honda replacement lamps work perfectly.

 

Blue gel filters transferred to new lamps.

Blue gel filters transferred to new lamps.

Now screw the new lamps into the board.

New lamps installed onto PCB.

New lamps installed onto PCB.

New lamps with filter socks installed.

New lamps with filter socks installed.

Now plug the board back into the unit and secure with screws again.

The CD version seems to also have a lamp or two behind the LCD display for backlighting.  This version has two lamps buried deeper inside.  Those use different lamps that are soldered to the board, which would require some more electronics skills and different lamps.  I didn’t deal with that here and will wait for them to fail before replacing them.

LCD backlight uses two different lamps soldered to another PCB.

LCD backlight uses two different lamps soldered to another PCB.  These were not replaced here.

Now just put the whole thing back together and plug it into the car for a test.  Have to do this after dark to see if all the lamps are lit.

All lamps on now even with radio off.

All lamps on now even with radio off.

Turning radio on adds LCD backlight.

Turning radio on adds LCD backlight.

$1.40 x 6 = $8.40 for Honda lamps.

#102 Power Steering Fluid Flush

July 5, 2014

Not trying to solve a problem here, just a little preventive maintenance (PM) to delay power steering failure.

As far as I know this car has mostly original power steering fluid in it.  Now 17 years old with 175K + miles on it, the power steering fluid was old and smelly so I decided to flush it and fill with fresh fluid.  Like many cars the Volvo 850 has no specified maintenance interval for power steering fluid so it usually gets overlooked.  I guess the manufacturers think the pump will be replaced eventually so you’ll get new fluid.  Problem with this idea is that the fluid does degrade with time and temperature and who knows what else.  Plus tiny metal particles that wear off in the pump and steering gear and swim around in there that could cut into seals.  So it’s just a good idea to flush the hydraulic system out and put fresh fluid in there every so often.

First thing to do is lift the front end of the car so we can rotate the wheels easily without scuffing up the tires and driveway.

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Front end on stands allows easy movement of wheels to flush the steering gear and hoses.

Next is to lay down some oil absorbent pads because this will be messy.

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Even when you work quickly and carefully some power steering fluid will be lost and drip onto the ground.

Started by dipping a strong magnet into the power steering reservoir and then rotating the wheel from stop to stop with the engine running.  Thought I would catch any metal particles that were stuck in there with this but was pleasantly surprised to see very few.  That means that the pump and steering gear aren’t wearing badly.

Dipped a strong magnet into the reservoir to capture any metal particles...

Dipped a strong magnet into the reservoir to capture any metal particles…

...but there were only a few tiny ones (good news!)

…but there were only a few tiny ones (good news!)

Next I used a bulb syringe to suck out as much fluid as possible from the reservoir.  This minimizes the mess in the following step.

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Sucked fluid out of reservoir.

Then I unclamped the power steering return hose at the reservoir and pulled the hose off.  This is where it gets messy as whatever fluid remains in the reservoir will leak down onto the alternator.  As quickly as possible I slipped a vinyl cap over the nipple to stop the flow.

Blue vinyl cap seals return port to keep fluid in reservoir.

Blue vinyl cap seals return port to keep fluid in reservoir.

    Fuzzy close-up view of capped return port. Hose just removed is to the right.

Fuzzy close-up view of capped return port. Hose just removed is to the right.

Next I slipped a length of 5/8″ clear vinyl tube over the hose just removed.  It’s just the right size to seal but still slip over the hose easily.  The other end of the hose went into my waste container.

5/8" clear hose slipped over return hose fits nicely.

5/8″ clear hose slipped over return hose fits nicely.

Other end of clear hose drains into waste container.

Other end of clear hose drains into waste container.

Filled the reservoir with fresh fluid.  Volvo spec for this is Dexron II or III or Mercon automatic transmission fluid (ATF).

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850 power steering fluid is specified to be Dexron-III or Mercon auto trans fluid (ATF).

It’s best at this point to have a helper to start/stop the engine and run the steering wheel back and forth. The basic procedure is to run the engine and quickly spin the wheel from left stop to right hard stop and repeat.  Fluid will quickly drain from the reservoir through the steering gear then back up and out to the waste container via the hose.  So you need to keep filling the reservoir while it’s draining.  If you’re working alone you have to work quickly and stop the engine before it runs dry, then refill frequently.

Flush with fresh fluid while draining into waste container.

Flush with fresh fluid while draining into waste container.

I ran about two quarts of fluid through to flush.  The old fluid was rather smelly, not quite burnt, and fairly dark.  Needed to be changed.  New fluid has a mild odor and is a transparent red color.

Old fluid was dark and smelly.

Old fluid was dark and smelly.  Half of what you see here is fresh fluid from the flushing process.

Then you re-connect the return hose to the reservoir and re-fill the reservoir.

Re-clamp return hose in position on the pump reservoir.

Re-clamp return hose in position on the pump reservoir.

Run the engine again while spinning the wheels back and forth until all air is bled out of the lines (no more foam).

At this point we’re done flushing and we just need to make sure the fluid level is correct.

Lower the car back down to a level surface and re-check fluid level.  Add or remove fluid as needed.  It’s probably a good idea to check the level again in a week or so in case there was still some air in the system.

$6 for three quarts of ATF.

#101 Exhaust Leak/Muffler Holes-Temporary Patch

June 29, 2014

Noticed a different sound from the car when standing next to it while idling. Sort of a sharp gurgling sound that seemed to come from under the left rear passenger seat.

Crawled under there with the engine running and could feel exhaust pressure coming from several holes in the muffler. Oh boy, time to repair or replace.

Multiple holes in bottom of muffler of varying sizes.

Multiple holes in bottom of muffler of varying sizes.

Exhaust leaks are potentially dangerous if deadly carbon monoxide (CO) creeps into the cabin.  If the floor is solid and tight, not much exhaust can get in but cabins aren’t always exhaust-tight.  For this reason automotive inspections don’t allow exhaust leaks ahead of the tailpipe.  Better play it safe with this and fix the leak, even if we have several months left on the state inspection tag.  The proper way to repair this is to replace the muffler but right now we don’t have the time or money to do this.  So I’ll patch it temporarily to fill the leak and make it safe until we can have the muffler replaced.  Basically buy us some time to do it right.  I’m also curious to see how long this method holds up before it fails or more holes break open.

If they are not obvious, one good way to check for exhaust leaks is to block the tailpipe with a rag or something.  The engine should stall if the exhaust is tight.  If you block the tailpipe and the engine stays running  you can locate leaks by listening for noise and feeling for hot gases.

I searched the internet for a variety of exhaust repair products.  Few had good reviews.  Found a couple of Permatex products at my local auto parts store that looked promising.  Both might work OK on their own and the package suggests that a combination of the two makes a secure, permanent repair.  I’ve learned not to trust marketing hype so am not overly optimistic.  If it lasts six months I’ll be content.

Tried using these two exhaust repair products from Permatex.

Tried using these two exhaust repair products from Permatex.

All exhaust repair starts with scrubbing loose rust and dirt off the metal first so I had to do some prep work.  The first layer of patching is a high-temperature (1000°F) paste or putty that is spread over the holes, then fired to cure it hard and strong.  The second product is a tape or bandage that is also cured with heat.

The patching procedure is presented in the photos below.

Close-up of holes in muffler before cleaning.

Close-up of holes in muffler before cleaning.

Chipped away loose rusty steel then cleaned hard with wire brush, followed by alcohol rinse and towel dry.

Chipped away loose rusty steel then scrubbed with wire brush, followed by alcohol rinse and towel dry.

Applied one coat of paste.  Putty knife didn't work well on this convoluted surface so used a gloved finger, pressing into the holes to seal.

Applied one coat of paste. Putty knife didn’t work well on this convoluted surface so used a gloved finger, pressing into the holes to seal.

Cured the putty with a heat gun.  Too much heat makes it soft and bubbly so went slow and methodical.

Instead of running the muffler hot, I cured the putty with a heat gun. Too much heat makes it soft and bubbly so went slow and easy.

The hardened light gray putty is hard and secure so is a promising fix.  Time will tell.

The tape/bandage would not stay secure hanging below the muffler at all.  The adhesive simply wasn’t strong enough so this was a disappointing experiment.

Bandage just wouldn't stick to muffler so I gave up on this second product.

Bandage just wouldn’t stick to muffler so I gave up on this second product.

Instead I slathered another coat of the putty over the first pass, hoping this helps even more.

2nd coat of paste is kind of thick and lumpy but hopefully makes it hold up well over time.

2nd coat of paste is kind of thick and lumpy but hopefully makes the patch hold up well over time.

Looks good and tight now and sounds much better.  No sound from below rear seat and I could feel no exhaust pressure under the muffler as before.  I’ll keep an eye on it to see how well it holds up;  will report if the putty fails.

Update 7/14/14:  The patch failed pretty quickly.  It seems that those four large holes had too much surface area to cover and the putty blistered out in a couple of spots from hot gas pressure and a couple of cracks formed so I can now feel exhaust pressure hissing through the new holes.

Cracked blisters allow exhaust to escape.

Cracked blisters allow exhaust to escape.

New muffler will be delivered shortly and I will replace it.  Check out those details on post #104.

$12.13 for two exhaust repair products

#100 Add Keyless Entry, Part 2

June 28, 2014

Wow! One hundred repair and maintenance tasks since we first got this car back in February 2012, along with 37 additional blog entries.  I would really like to post something exciting or significant for this century mark but the timing is just not right so #100 is relatively trivial.


As mentioned back in task #90 when adding a remote lock/unlock feature to this car, I planned to also add an alarm horn and dashboard indicator.  This makes the keyless entry/alarm system complete.

Picked up both the dash top indicator and alarm horn from wrecked cars in a salvage yard.  Removing and installing these was not as easy as I had hoped but worth the effort.

The red light (LED) on top of the dashboard just below the forward center of the windshield come in two flavors.  One is for cars with electronic climate control (ECC) and this one has an additional light sensor on the unit.  My first mistake was pulling one of these from a scrap car only to discover that the wiring connectors are different.

Alarm indicator (white bubble)  also includes light sensor for ECC equipped cars.  Not the right module for this car with manual climate control.

Module for alarm indicator (white bubble) also includes light sensor for ECC equipped cars. Not the right module for this car with manual climate control.

So the next time I visited a salvage yard I made sure to get the light unit with a single red light.

Lacking a factory alarm system the hole filler was in place on this car and that was removed by prying it out.  This was easy to do because the forward part of the dash just below the windshield was badly cracked, especially around this rectangular hole.

Removed filler piece to leave square hole for LED module.  Wiring is underneath.

Removed filler piece to leave square hole for LED module. Wiring is underneath.

The cars come pre-wired with most options and accessories so there was a functional wiring connector below the hole.  Fishing this connector out of the hole was much more difficult.  There is so little space just above the hole that I could not grab the wires to pull them out.  Neither is there any real room for manipulating normal tools down the hole.  Having very small hands or specialized tools would be needed.  Or removing the windshield, which would be a last resort.  Since I had to pull the entire dash out to repair the forward mounts being broken, I had direct access under there so pulled the wire through the hole and taped it on top.  It was already above the hole when I reinstalled the dash.

Then I simply plugged the new LED module in and verified that it blinked when the doors were locked.  I had to glue it in place with black silicone because the dash was so badly cracked and broken (probably because of broken front dash mounts) that there were no solid edges to hold the unit in place.  Looks amateurish but you don’t really notice it unless you’re looking for problems.

Since square hole was really broken, the module would not snap into place.  Had to glue it down with black silicone.

Since square hole was really broken, the module would not snap into place. Had to glue it down with black silicone.

Blinking red light is most visible in low light and tells you that the car is locked and may be a deterrent to a thief.

Blinking red light is most visible in low light and tells you that the car is locked and may be a deterrent to a thief.

The horn is also pre-wired whether or not the alarm is installed.  Access requires removing the cowling behind the hood just in front of the windshield.  Some effort but not too bad, about a half hour total.  A single bolt holds the horn in place.  I just removed the cowling and bolted the “new” alarm horn in place, then plugged it in and tested it before replacing the cowling and wipers.

Photo essay below is the basic procedure for installing the alarm horn.

Empty place where alarm horn will go.  Wiring harness plugged into dummy plastic holder.

Empty place where alarm horn will go. Wiring harness plugged into dummy plastic holder.

First step is to remove both wiper arms.

First step is to remove both wiper arms.

Remove large and small weather seals from cowling.

Remove large and small weather seals from cowling.

Disconnect cowling drain hoses on both sides.

Disconnect cowling drain hoses on both sides.

Remove five screws securing cowling to chassis.

Remove five screws securing cowling to chassis.

Pull cowling out and set aside.

Pull cowling out and set aside.  This is also a good time to shake out loose debris from the cabin air filter.

Here is the alarm horn with bolt needed to secure it.

Here is the alarm horn with bolt needed to secure it.

Pull sealing plug out of alarm horn bolt hole and discard.

Pull sealing plug out of alarm horn bolt hole and discard.

Bolt alarm horn onto chassis.

Bolt alarm horn onto chassis.

Alarm horn in place.

Alarm horn in place.

Unplug wiring connector from dummy bracket, plug into horn and discard bracket.

Unplug wiring connector from dummy bracket, plug into horn and discard bracket.

Tested horn function by holding in the panic LOCK button on the remote keyfob.

Then re-installed the cowling, weather seals and wipers.

Cowling back together with wipers back on and horn in place.  Ready to roll.

Cowling back together with wipers back on and horn in place. Ready to roll.

$10.16 for alarm horn and dash indicator from wrecked cars in salvage yard.

 

 

#99 Safety Repair of Rear Brakes

June 15, 2014

Alert reader Ken Gill sent a message about a problem with the rear brake job in post #70.  He experienced the same thing and observed that I had not driven home the caliper guide/retainer pins.  They could not be hammered secure because the retainer ferrules were too large.  I failed to realize this and mistakenly thought they were secure enough.  Boy, was I wrong.

This safety task was to fix the problem with very loose and nearly inoperative rear brakes because of the loose pins.  Scary because my girls were driving around for months with faulty rear brakes.  I also updated the original post with a lengthy description of the situation and remedy.  This is an important safety issue so please read my comments if you have any concern that your rear brake pins are secure.

All better now, thanks to Ken’s heads up.

Which reminds me to ask for reader comments when you see something on this blog that was done wrong or could be improved.  We have hundreds of readers all over the world (on six continents!) who find it useful for DIY 850 drivers.  I want it to be complete and correct, so don’t be shy.

#98 Replace RF Corner Light Assembly

May 14, 2014

One day we noticed that the lens was missing from the right front corner light (front parking/turn signal lamp) assembly.

My first thought was vandalism where somebody smashed it but after examination I observed that the lens that wraps around from font to side was completely gone with no trace of damage.  It seems that the factory light assemblies have the lens secured with adhesive or tape.  Now I’m guessing that the glue simply came loose after 17 years of heat, sunlight and vibration and that the lens simply fell off while driving down the road.

Lens missing

Lens missing

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Fortunately the lamp housing was still attached to the car and functional so no worries or hurry here.  Bonus that the Volvo part number is molded into the lamp housing and visible so I just wrote that down and went searching for replacements.  Had a hard time identifying this part on my favorite factory parts locator, volvopartswebstore.com, or in Vadis so I really did need the part number.

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This particular part is Volvo 6817774 and costs over $70 with shipping for a new factory part.  That’s a little steep and I was hesitant to get a junkyard replacement because they are likely to be in poor condition.  After looking I couldn’t find any at a scrapyard anyway.  Back to the internet, I did find what appears to be a high quality aftermarket replacement with good customer reviews from Amazon.  Ordered one only to have the supplier inform me the next day that there is a recall on that part so they wouldn’t ship.  So I ordered another part on Amazon and it looks great.  Apart from plastic color I can’t tell much difference between the factory original part and this one.

Good news for this task is that it doesn’t require any tools.  Just open the hood and release the spring holding the assembly in place.

Removing old lamp assembly with missing lens.

Removing old lamp assembly with missing lens.

After unplugging the wiring harness we can work on swapping a couple of parts.

Remove spring and lamp socket from old assembly.

Remove spring and lamp socket from old assembly.

Side-

Side-by-side comparison of the old and new light assemblies.

Install spring and socket onto new light assembly.

Install spring and socket onto new light assembly.

Now just put the new assembly in place by plugging the harness in and inserting the module in place and locking with the spring hook.

New light assembly installed.  Looks beautiful.  Original one on left side seems hazy and crusty in comparison.

New light assembly installed. Looks beautiful. Original one on left side seems hazy and crusty in comparison.

Did a quick check of light function with running lights and turn signal.  Working fine so we’re done with this one.

Functional checkout OK.

Functional checkout OK.

Now I’m keeping an eye on other light assembly lenses on both cars to see if they show any signs of coming apart, or if this was a rare event.

$22.50

Update 7/8/15:  Lenses popping off all over the place and readers (below) seeing the same thing.  See my post entitled, “Corner Light Epidemic”.

#97 Replace Shift Knob

May 11, 2014

As mentioned in post #95, I scraped the top off the shift knob when wrestling the dash back into place.  I was planning to replace it eventually because even before this damage the knob was in rather poor shape.

Note: this applies to the automatic transmission (transaxle) 850 variants so likely only the North American readers will be interested in this.  But I would love to hear from people in other continents who have automatic transmissions to gauge how common it is outside North America.

Tore shift knob up when replacing dash.

Tore shift knob up when replacing dash.

Original knob was already in bad shape.  Top had a heat-melted plastic look and feel with lots of cracks.  You can still see what it looked like on the top right.

Original knob was already in bad shape. Top had a heat-melted plastic look and feel with lots of cracks.  You can still see what it looked like on the top right.

Pulled a couple of knobs in varying condition from a scrapyard at a very good price (see previous post on this if interested).

Two shifter knobs pulled from scrapyard cars.

Two shifter knobs pulled from scrapyard cars.

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One knob was a matching dark color and had an intact release button but it was fairly cracked.  Still better than knob now in car.

The vinyl coating on the other knob was in excellent condition but it was a lighter color tending toward brown.  It had a broken release button.

I prefer the knob in better condition despite the color so needed to swap the release button with the other knob.  This isn’t terribly difficult but it does take some mechanical dexterity.  And the otherwise excellent instructions found on IPD for a shifter knob repair kit gloss over a very important step of getting the upper pin into a slot in the plastic lever inside, which takes some manipulation.

The spring which apparently fails frequently (enough to create a repair kit) was in good condition so I just swapped the good button to the good knob.

Push old button out by prying after moving it out with a screwdriver from inside.

Push button outwards by pulling with fingers after moving it out with a screwdriver from inside.

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Release spring from button, then push pin out to release upper part of button, then unclip lower part to remove button.

Now I have a good button to transfer to the good knob.  Repeated this button removal for the good knob to remove the broken button.  Then I installed the good button onto the good knob:

Clipped good button onto bottom of good knob and then positioned spring properly onto button.

Clipped good button onto bottom pin of good knob and then positioned spring properly onto button.

Pulled internal lever out to line up with upper pin, then secured pin in slot.

Pulled internal lever out to line up with upper pin, then secured pin in slot.

Then I just pushed the button all the way in and it was ready to go.

Now that I had a new knob assembly in good shape, it was time to replace the knob.  It’s much easier to pull the knob when the shifter is in the neutral position.  Obviously not when the engine is running, and you can do this by inserting the key and turning it one or two clicks clockwise without starting the engine.  Then push the shiftlock override button in and move the shifter to the middle.

Move shifter to neutral position with engine off by turning key partially then pushing shiftlock override button while moving lever.

Move shifter to neutral position with engine off by turning key partially then pushing shiftlock override button while moving lever.

Removing the old shifter knob isn’t terribly hard; you just pull it straight up very hard.  I get better leverage while kneeling on the passenger seat than when sitting in either of the front seats.  It’s also more ergonomic and easier on my lower back.

Pull straight up (rather hard) to remove shift knob.

Pull hard straight up to remove shift knob.

Then installed the new knob by simply pushing it down into place and then pulling the leather-like boot covering the shaft back up to the knob and snapped into place.  The plastic tangs at bottom of the knob clip under a square plastic ring inside the sleeve.

Pulled leather-like cover (boot) back up to knob and locked into place.

Pulled shaft sleeve back up to knob and locked into place.

All done and the new knob looks better than it appears in the photos in real-life.  There are several different shades of gray in this interior anyway.

New shift knob installed, ready to go.

New shift knob installed, ready to go.

$5.54 for two shift knobs removed from scrapyard cars.

Box of Scrapyard Parts

May 10, 2014

For various reasons I needed quite a few parts to replace or add to the car and several of these are either unavailable or expensive.  At times like these it’s good to have an automotive salvage yard (junk yard, scrapyard, wrecking yard– whatever you want to call it) nearby with several 850s.  As mentioned in the post on where to get parts, the scrapyard is an excellent source of used parts, particularly for large and/or expensive pieces.  The downside is that they may not have the part on a car (or the wrong color) and the condition is always as-is, so plastic and rubber parts will be dry and brittle.  It’s also messy as you are climbing in or around wrecked cars and you need to bring the right tools to remove whatever part you want.

All that said, I think it’s worth the trouble and scored a boxful of parts, mostly from one 1997 850 that hadn’t been picked clean yet.

Miscellaneous parts pulled from an 850 in a salvage yard.

Miscellaneous parts pulled from a few different 850s and an S70 in a salvage yard.

This assortment includes a couple of dash speakers, steering column upper/lower shrouds, heated air intake pipe, alarm buzzer/horn, dash cover alarm light, recirculating air damper motor, two shift knobs, a muffler hanger and two dash end defrost trim pieces.

Will mention installation of these parts in future posts.

The scrapyard is an hour drive each way and I spent almost two hours in the yard but it was worth the trouble.  Cost was very low for all this: $42.

For those of you who haven’t experienced a junk yard pull, here are photos of cars typically found in a scrapyard.  It’s a little creepy when there are personal effects left in the wrecked cars.  The cars are frequently a real mess with loose parts strewn all over so it’s often a lot of work to pull a part that you need, if the parts are even still with the car.

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#96 Visor Repair

April 21, 2014

Driver’s side sun visor was worn where it clips into the roof so that it was loose and vibrating and would easily pop out of place.

Vinyl worn off so that visor was loose.

Vinyl worn off so that visor was loose.

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The proper fix would be to replace the whole visor but that would be expensive as a new part or would likely be fairly worn as a used or salvage part.

Started a repair by carefully cutting away the remaining worn vinyl around the retaining rod where it clips to the roof.

Repair begins by cutting away worn/torn vinyl from rod.

Repair begins by cutting away worn/torn vinyl from rod.

First tried to increase the diameter of the rod to match the clip by slipping some plastic tubing over it.  Even when I cut a diagonal line, this popped off the rod when unclipping from the roof.

I really couldn’t think of a good solution to slip on or clip on something that would increase the diameter of the rod.  So I tried using epoxy putty to build up the diameter.  It’s hard to get it nice and smooth and just the right diameter but I did as best I could.

Applied epoxy putty around rod to build up diameter.

Applied epoxy putty around rod to build up diameter.

I made the diameter of the epoxy so that it is snug in the clip.  It cures quite hard and adheres well.  The putty can be filed or sanded smooth but I don’t think I need any refinements.

Visor now snaps in tightly.  A little ugly but works well enough.

Visor now snaps in tightly. A little ugly but works well enough.

This works quite well, at least for now.  Snaps in and out well and rotates up and down.  We’ll see how well it holds up long-term but it should be stronger than the original vinyl.

$0 no cost for epoxy putty I had in hand already.

#95 Repair Broken/Loose Dashboard

April 20, 2014

Well, this was a big project, taking up a large chunk of my Easter weekend.

I grew tired of listening to the dashboard rattle and squeak with minor road disturbances and my daughters who normally drive this car confirmed that this nuisance bothered them as well.  At first I thought it was due to deteriorated cushions in the dash top cover or pad.  So I removed the top pad and found no real cause of squeaking or rattling, such as a worn foam strip.  This was also my last chance to do anything big before one daughter soon returns from her semester abroad, as the car would be un-driveable for a few days.

Dash pad/cover removed to look for looseness/squeaks.

Dash pad/cover removed to look for looseness/squeaks.

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Did a little research online and learned that the 850 has a very common problem with the front dashboard mounts failing, resulting in the whole front of the dash to be loose.  That’s what causes all the rattling and squeaking. This was verified on this car when I found I could move the whole dash freely front to back with the pad off, meaning the front bolt mounts were completely broken free.

So I removed the dash entirely to find what I expected:  the front mounting tabs (nut retainer plastic) had torn away completely from the dash assembly.

Front mount broken off, remained in place when dash was removed.

Front mount broken off, remained in place when dash was removed.

One mount completely ripped out of dash, leaving gaping hole.

One mount completely ripped out of dash, leaving gaping hole.

All four mounts broke and stayed on chassis when dash was removed.

All four mounts broke and stayed behind on chassis when dash was removed.

Fortunately the mounts were somewhat intact, not shattered into many small pieces as some people find.  This meant a relatively easy repair, and I adapted fixes as suggested by several people in Volvo forums.  Repair was easy but getting the dash out and re-installing is quite an ordeal.

First I used cyanoacrylate (Super Glue) to secure the broken plastic mounts back into place.

Super-glued mounts back into position as best as possible.

Super-glued mounts back into position as best as possible.

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Then I applied epoxy putty to the broken joints for a stronger bond.  These two steps are intended only to get and keep the nut in position temporarily; they are not expected to hold firm.

Putty epoxy used to further secure mounts in place.

Putty epoxy used to further secure mounts in place.

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Then I screwed a short length of metal pipe strap over the mounts to create the new fastener.  The repaired mount now consists of the strap secured to the dash with the nut captured underneath.  Located the large holes directly over the nut thread.

Metal pipe strap screwed into dash forms new mount.

Metal pipe strap screwed into dash forms new mount.

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Repair looks cheesy but it is solid and really works.

All four mounts created by strapping over nuts.

All four mounts created by strapping over nuts.

Verified mounting screw cleanly passes through metal strap.

Verified mounting screw cleanly passes through metal strap in all four positions.

Re-installed the dash and was pleasantly surprised that all four repaired mounts held together and I was able to tighten them all down.  I was going to be happy with only three solid ones and settle for two.  Four is just totally sweet!

Update 4/24/14:While others have concerns about the exact positioning and contour of the strap, I found it was not critical.  The strap was loosely wrapped around the mount shape in some cases.  Also had no trouble getting the long bolts to line up with the captive nuts.  For those who are curious, I used #8 truss head self-drilling screws, 1/2″ long, using care not to over-tighten them and strip the plastic.  I verified strength by prying hard under a couple of straps to make sure the screws would not rip out easily.  If the screws were to pull out, I would use blind rivets to secure the straps instead.

After the dash was mounted back in place I re-installed the dash pad and put everything back together.

No more rattling or squeaking now.

The process of removing the dash pad and dash is too involved to detail here.  Here is a look at everything removed for this procedure:

Everything removed for this repair.  Quite a task.

Everything removed for this repair. Quite a task.

A load of parts removed.

A load of parts removed.

An experienced person can probably do this task in one long day.  I spent parts of three days to do it all.

Strange to see the car with the whole dash removed:

Entire dash removed as seen from left side...

Entire dash removed as seen from left side…

...and right side.

…and right side.

Technically you can remove the dash with the dash pad/cover in place but it is that much heavier and hard to maneuver if you leave it on.

Update 4/24/14: The dash pad plastic is now so old and brittle almost any disturbance of it is sure to cause damage beyond what is likely already underneath.  This one had a lot of big cracks and chunks broken off.  In addition it is difficult to get these back into place properly, especially at the right corner above the center vents.  I would recommend not removing the pad/cover unless needed for other repairs.

Also, if your air conditioning evaporator is leaking (common problem), this is the best time to replace it because dash removal is required for that repair as well.

When removing and replacing the dash, use caution around the shift knob.  I tore this one up by scraping the dash over it.  Better to move the knob back out of the way if you can’t be extra careful.

Tore shift knob up when replacing dash.  It's OK because it was crusty already and I have intended to replace it anyway.

Tore shift knob up when replacing dash. It’s OK because it was crusty and gummy and I have intended to replace it anyway.

$0- No cost beyond some glue, weld and pipe strap, which I had around the house.

#94 Steering Wheel Cover

April 13, 2014

The steering wheel on this car is getting really worn and rough.  It is uncomfortable to grip it so I need to do something.

Wheel was worn rough; uncomfortable to grip it.

Wheel is worn and rough; uncomfortable to grip it.

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Tried softening the rough patches with a heat gun but it didn’t flow and even if it did it would be smooth instead of textured for better grip.

So my choices are to replace the steering wheel or cover it.  A replacement wheel would be expensive and a fair bit of work so I chose to try the cover approach.  Got a gray after-marked cover that looks nice and seems to fit well.  It’s a tight fit and took some muscling to get it on but very do-able.

Installed slip-on cover.  Looks and feels nice.

Installed slip-on cover. Looks and feels nice.

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Camera flash exaggerates color contrast. In real life, the cover looks darker and is a closer match to the steering wheel.

If this doesn’t work I will try the more expensive lace-on covers that are customized for each car model.  They require some time and effort to install but are quite nice.

$8.96 for slip-on cover

#93 Front Speaker Replacement

April 6, 2014

Since I had been driving this car to work recently, I noticed all sorts of little things that need attention.  My commute is at least a half hour so I listen to the radio quite a bit.  The speaker in the driver’s door was dead and that became quite obvious in a hurry.  It seemed like I lost hearing in my left ear because there was little sound from the radio on that side.  This was confirmed by playing with the L-R balance control and F-R fader to localize the dead loudspeaker.

So I investigated to see if it was the speaker or the wiring that was misbehaving.  Can’t be the amplifier since I get sound from three other speakers on the left side.

Removed the driver side speaker by prying off the grill and then unscrewing the speaker.

Door speaker with grille removed.  Four screws secure the speaker itself.

Door speaker with grille removed. Four screws secure the speaker itself.

While attempting to disconnect the wires from the speaker, the blue terminal block popped off and two wires with it.

Blue terminal block snapped off when pulling wires off.

Blue terminal block snapped off when pulling wire disconnects.

It’s hard to get access but I measured resistance across the voice coil wires with a multimeter and found them to read around 4Ω as expected, meaning the speaker coil is OK.

In this design the voice coil wires are soldered to the flexible terminal wires and glued to the speaker cone.  While this arrangement may be common, I believe it is a poor design because the mechanically fragile solder joint is constantly vibrating and will probably fail over time.   I surmise that one of the joints failed and came loose which is why the speaker stopped working.  The other one may have been weak and popped off easily when the terminal block broke away.

Poor solder joints glued to speaker cone.  Not a good design.

Poor solder joints glued to speaker cone.  Not a good design.

Flex wires separated from contact solder joints.

Flex wires separated from contact solder joints.

It is nearly impossible to re-solder these flex wires to the voice coil because of a small opening and very short leads.  And  a factory speaker from a salvage car is likely to suffer from the same problem.  So a new speaker is in order.  Factory speakers are rather expensive so I decided to get a decent quality low-cost after-market replacement.  To sound the same on both left and right sides, these speakers should be replaced in pairs, which is how they are usually sold anyway.

Factory speaker.

Front door factory speaker.

Main specifications are 4Ω impedance and 4 inch (100mm) diameter.  Power rating is not critical with the factory amplifier which is relatively weak.  There are many different ways a person could replace these but the following is how I chose to do it.

At Crutchfield I found what seem to be decent speakers at a very good sale price ($20 per pair).  Customer reviews are generally favorable and most people report a big improvement over factory speakers on most cars.  Looking at the one that came out of the car I don’t think they are particularly good; seem to be very cheap and basic.  I didn’t want to put much money into these speakers (people often do spend a lot for speakers) but at this price I thought I’d take a chance.

These new speakers are actually coaxial with a tiny tweeter over the woofer (mid/bass) cone.  On the 850 the front tweeters are up in the dash pad where the highs reflect off the windshield.  So these coaxial replacements will add some highs to the front.  This helps because I also tore one of the tweeter cones when working on the dash earlier so it isn’t performing well anyway.

Crutchfield’s replacements are slightly smaller.  The speaker cone is 3-1/4″ compared to the factory 4″.  The package seems much smaller because the original speaker had a wider metal frame and surround (the flexible part connecting the cone to the frame).

Front side of original and new speaker.

Front side of original and new speaker.

Back side of original and new speaker.

Back side of original and new speaker.

Because it’s smaller, the mounting holes are about 1″ further in, meaning I had to adapt the mounting. It’s much easier to work on this outside the car so I removed the speaker frame from the door.

For mounting adapters I used plastic cable clamps and cut the loop off, then screwed these strips into the bracket.  The lower right screw fastens directly to the door so I just used a screw to loosely locate this adapter.

Cut plastic cable clamp just past where it starts to curve and trimmed sharp corners.

Cut plastic cable clamp just past where it starts to curve and trimmed sharp corners.

With four adapter strips fabricated and installed I marked where the new speaker holes should be and drilled a small starter hole.  Then used short self-tapping screws to bite into the plastic adapters.

Adapter strips installed on speaker frame.

Adapter strips installed on speaker frame.

New speaker screwed into adapter strips.

New speaker screwed into adapter strips.

I was concerned that these thin plastic strips might not be strong and secure enough but they held together very well even when I pulled on the speaker.  I’m confident this adaption scheme will last a long time.

The new speakers have different sized disconnect terminals so I had to cut the original connectors off and splice in to the wiring adapters provided with the speakers.

Spliced in adapter wires to match new speaker terminals.

Spliced in adapter wires to match new speaker terminals.

Now I could install the speaker frame back into the door and secure that fourth (lower right) adapter strip.

New speaker adapted, installed and wired, ready for sound check.

New speaker adapted, installed and wired, ready for sound check.

Ready for audio check and it worked very well; sounds clear and loud and has a lot more high-frequency response with the coaxial tweeter built in.  Not audiophile grade speakers but to me they sound slightly better than the original speaker.

Snapped the cover back over the speaker and we’re ready to do the same for the right (US passenger) side speaker.  Even though that speaker still works, it should be replaced to match sound quality.

Other people might want to upgrade their sound system in the same situation or just get higher-quality speakers.  I was more interested in being cheap but keeping sound at least as good as factory speakers.

Update 4/10/14:  When I replaced the passenger (US right) side speaker, I tried doing the work in the car without removing the speaker frame from the door.  Turns out this works fine and a little less work.

New speaker on right side installed without removing frame from door.  Works well.

New speaker on right side installed without removing frame from door. Works well.

New speaker installed in passenger side.

New speaker installed in passenger side.

$20 for an inexpensive but decent set of coaxial speakers.

#92 Evap Leak/P0455 (Roll-Over Valve Hoses Cracked)

March 24, 2014

Check engine light came on with trouble code P0455 (evaporative emissions large leak).  Reset it and made sure the gas cap was tight on the fuel tank but the error came back.  This indicates a significant leak in the fuel tank or hoses or evap components leading from the tank to the intake manifold.  For some months now we have had random large and small leak codes pop up but we could reset them for awhile.  Now it’s permanent so hopefully I can find a problem.

Began sniffing around with my combustible gas leak detector (a useful tool for locating fuel leaks in a post dated 1/19/14) and registered a big leak under the car around the fuel filter.

After lifting the car to crawl around and inspect the area, I found that the leak was not at the fuel filter or fittings but just above the filter towards the rear.  Looking carefully I spotted a separated line:

Evap line separated from roll-over valve.

Evap line separated from roll-over valve.

The rubber coupling from the roll-over valve to the evap line going towards the engine area had deteriorated and actually separated.

Hose separation at roll-over valve just above and behind fuel filter.

Hose separation at roll-over valve just above and behind fuel filter.

Evap line separated from roll-over valve.

Evap line separated from roll-over valve.

This is sure to trigger the large leak error because the fuel tank is wide open to the roll-over valve via the fuel evaporation collection tube.

Started repair by removing the roll-over valve from the fuel pump bracket to gain access.  Just one bolt holding it in place.  Here I discovered that the hose on the inlet side of the valve was also cracked and nearly separated, so both ends need repair.

Removing roll-over valve revealed separated tube coupling on inlet side as well.

Removing roll-over valve revealed separated tube coupling on inlet side as well.

??????????

Removed the broken coupling hose ends from the roll-over valve and the tube ends.

Broken hose pieces carefully removed from roll-over valve to avoid damaging plastic nipples.

Broken hose pieces carefully removed from roll-over valve to avoid damaging age-brittled plastic nipples.

Broken coupling hose removed from both plastic tube ends as well.

Broken coupling hose removed from both plastic tube ends as well.

By the way, this is one of the dirtiest jobs I’ve experienced working on this car.  Manipulating the roll-over valve and tubing requires working up under the car and years of dark crud flaking off and landing in your face and all over your body.  Even wearing safety glasses I got black flakes in my eyes so plan for a mess.

Here is where it gets interesting. The plastic evap tubes measure 7.5mm and the roll-over valve nipples are 6mm, so they are unequal in diameter.  The coupling hose has two different diameters:

Broken coupling hose shown to demonstrate tube size difference.

Broken coupling hose shown to demonstrate tube size difference.

I wanted to avoid buying the factory parts to save time and cost so for this car I used some 1/4″ (6.3mm) ID heater hose from an auto parts store.

1/4-in hose is loose but workable at roll-over valve end and very tight at evap tube end.

1/4-in hose is loose but workable at roll-over valve end and very tight at evap tube end.

The hose fits reasonably snugly on the roll-over valve nipples.  A 6.5mm ridge or barb helps the fit, and a little petroleum jelly smeared on the nipples helps make the seal.

It’s harder pushing the undersized hose onto the plastic tubes but I was able to get about 1/2″ of engagement.  A little petroleum jelly helps lube it and twisting the hose also helps force it on.  It’s difficult to get arms and hands into the area of the tank tube so that was challenging but I managed to push the hose onto the tube.

Pushing hose onto tank tube is difficult but can be done.

Pushing hose onto tank tube is difficult but can be done.

They certainly don’t pull off easily but I would have liked the hose to slide over the tube a little longer.

Cut the tubing in lengths to roughly match the original coupling hoses.  Slipped both ends onto the valve and then bolted it back into place.

All put back together using 1/4" hose.

All put back together using 1/4″ hose.

Time will tell for this one but it should work.  Have to drive it around for a while to see if an evap leak code comes back.

$0.69 for hose (1ft@69 per foot)

My 850 sedan has frequent evap leaks as well and I suspect the same thing is happening to that car.  Based on my experience using straight hose I decided to bite the bullet and buy real Volvo coupling hoses for the other car.  Replacement procedure is the same except that it is easier to slip the hose onto the tube ends.

Update 4/9/14: Replaced both hoses on the sedan using the factory parts this time.  Rear hose coming from fuel filler neck was badly cracked and split.  Front hose was crusty but not obviously leaking.

Sedan hose cracked at rollover valve on rear side.

Sedan hose split at rollover valve on rear side.

Factory coupling hose with two different tube sizes.

Factory coupling hose with two different tube sizes.

With these factory hoses, the plastic tubing end was now easier but the roll-over valve ends were harder to slip over.  This is  opposite of when I used the straight 1/4″ tubing as done originally.

New hoses installed both sides of roll-over valve.

New hoses installed both sides of roll-over valve.

$35.01 for two Volvo tube couplings

By the way, I plan to write up a posting on the evaporative emissions system and how to isolate and check for leaks in it.  It will also cover how the car determines faults in the system.

Technical Notes

Original rubber parts including most hoses on cars this old (newest model 850 is now 17 years old) are guaranteed to be bad or on their way there.  This is because they slowly dry out and become hard and brittle, losing their elasticity.  Heat, chemicals and vibration contribute to the problem.  Point being that the vacuum and evap hoses or elbows on these cars will all likely need to be replaced.  One might do it proactively or just deal with them as problems occur.

Counter-intuitively, the roll-over valve is not part of the fuel supply line.  It prevents fuel in the tank from flowing towards the evaporative emissions charcoal canister in case the car is upside-down or on its side, in which case the evap tube might be directly in contact with liquid fuel.  Basically a safety device, cheap and simple way to minimize fire risk.

Caution When Working on Front Seats

March 18, 2014

Recent activity on front seats in both of our 850s inspired me to post a word of caution when working on the seats.  Most 850 front seats have a side impact protection system (SIPS) which is really just an air bag that pops out of the seat.  In theory if the car were struck from the side hard enough to deform the front seat bottom, the air bag would deploy and provide some cushion against injury to the torso.

Unlike the airbags in the steering wheel and front passenger dashboard panel, these SIPS bags are not operated by electronics using a deceleration sensor.  Instead, they are pyrotechnic devices that work physically.  When the trigger is struck the cushion deploys instantly.  No electronics involved.

1-Sensor, 2-Firing Circuit, 3-Air Bag

1-Sensor Unit, 2-Firing Circuit, 3-Cushion Module

Note how air bag pops out the back towards the front, protecting occupant's ribcage.

Note how air bag pops out the back towards the front, protecting occupant’s ribcage.

There are a couple of interesting videos on YouTube where a seat air bag is deliberately triggered to demonstrate exactly how it works:  Video 1  ,  Video 2    It’s not obvious from the videos but bag deployment is loud, like a shotgun blast.

Now to the point of all this.  When working on or around the seats, if there is any chance of striking the sensor accidentally, you should install the special safety device designed to minimize probability of unintentional deployment.  If your face was near the seat you could be seriously injured or suffer hearing loss when the bag explodes.

Volvo considered this hazard and so provides a safety device under the front seat side pocket.

Safety device stowed in seat side cover.

Orange safety clip stowed under seat side pocket.

The seat pocket assembly is removed by moving the seat forward, lifting the rear up and then towards the front to release, then lift out.

Risk of accidental air bag deployment if sensor is struck hard enough.

Risk of accidental air bag deployment if sensor is struck hard enough.

Safety device minimizes risk of unintentional air bag deployment when working on or around front seats.

Safety device minimizes risk of unintentional air bag deployment when working on or around front seats.

Obviously you need to remove the safety device when done working on or around the seats and put the seat pocket back in place.

Technical Notes

SIPS Description and Operation

General Information
The SIPS bag is activated by certain side impact collisions and is designed to help increase protection to front seat passengers.

The SIPS bag is being introduced as standard equipment in some markets and as an option in others, beginning with model year 1995.

The SIPS bag system consists of three main components:

  1. Sensor unit
  2. Firing circuit
  3. Cushion module

Sensor unit
The sensor unit is located in a sensor mount at the outer end of the forward SIPS tube. The mount is the part of the chair that protrudes the most toward the inside of the door.

A pressure plate is mounted forward of the sensor unit. In the event of a collision, the pressure plate transfers the force from the inside door panel to the sensor unit.

Firing circuit
The pyrotechnic firing circuit runs through the seat back and under the seat cushion.

The firing circuit consists of two tubes coated on the inside with a pyrotechnic material. When triggered, the signal is transmitted as a shock wave.

The tubes are covered with a black protective sleeve to protect them from mechanical damage.

SIPS-bag cushion module
The cushion module is located on the seatback frame to help provide protection to the driver/passenger where the rib cage is closest to the inside door panel.

Cushion
The cushion, made of silicone-coated polyamid fabric, is folded under a cover. When inflated, the cushion has a volume of about 12 liters (0.4 cubic feet).

Gas generators
Two gas generators inflate the cushion. When activated, the gas generators produce a harmless gas which inflates the cushion very quickly.

Functional description, general
The SIPS bag is a separate system in each front seat. There is no connection between the two SIPS bags. In the event of a certain side impact collision, the SIPS bag will be activated only on the side of the collision. The sensor unit is a pyrotechnic impact sensor, which will be activated only if it is struck with an impact that causes the deformed door to hit the sensor with a speed of about 2 m/s (6.6 ft/sec). The system is calibrated to avoid unnecessary activation such as by a blow to the door or a light impact with a stationary object.

The pressure plate will deform the aluminum cover, pushing a firing pin and releasing the ignition charge. The ignition charge creates an impulse which is transmitted through the firing circuit as a shock wave. When the shock wave reaches the cushion module, it ignites the powder charge in the gas generator.

When released, the gas blows through a firing chamber tube and into the cushion. Activation of the first gas generator occurs immediately and the second is activated after a delay of about 3 milliseconds. The delay is designed to maintain the pressure and volume of the inflated cushion for an adequate time.

During inflation, the cushion breaks open the cushion module cover, rips open the chair upholstery seam and pushes out to inflate to its full volume. The cushion inflates toward the door panel to help protect the passenger’s rib cage during the collision. There is a vent though a hole in the cushion, so it will collapse slowly enough to act as a brake on the driver/passenger.

There is no diagnostic system or warning lamp connected to the SIPS bag.

The SIPS bag is available only in cars equipped with the SRS system, and it is always installed in both front seats.

SIPS-bag Components

SIPS Components

Sensor-unit components

  1. Sensor housing
  2. Aluminum cover
  3. Spring washer
  4. Firing pin
  5. Compression washer
  6. Ignition charge
  7. Transport safety device

Cushion module components

  1. Cushion
  2. Gas generators
  3. Firing chamber
  4. Mount

Re-Covering Leather Seats

March 18, 2014

Being lazy like most people when it comes to maintenance, I let the leather seats deteriorate in my 850 sedan.  Small cracks became large ones until they tore open.  Once that happened the holes just got bigger and even the foam cushion started to wear off.

Driver seat leather cracked,  torn and worn mainly on bottom.

Driver seat leather cracked, torn and worn mainly on bottom.

Seat cushion foam is even breaking off.

Seat cushion foam is even breaking off.

Common problem on cars this old.  Cloth and leather take a lot abuse, mainly when climbing in and out of the car since you pretty much have to slide across the seat to get in.

Besides being ugly, it was actually uncomfortable to sit on this, especially wearing shorts.  So I had to do something to fix the problem  Being a solo occupant 90% of the time, the other seats are still in good shape so this is a one-seat repair.

Tried using the cheap seat covers which look OK but the bottom pad is loose and just slides around, making sitting down a real chore.  Gave up on this idea quickly.

Simple cushion would work to cover damage if bottom pad could be fixed in place.

Simple cushion would work to cover damage if bottom pad could be fixed in place.

Tried custom-fit covers which take a fair bit of effort to install.  There were straps all around but they really didn’t stay put on the bottom and they were fairly thin anyway so I could still feel the damage underneath.  These went into the trash as well.

These fitted covers didn't work well for me.

These fitted covers didn’t work well for me.

Seems like re-covering is the only viable solution.  Purists will want to recover the seats with leather but it is very expensive.  Like $500 per seat plus a lot of work on top of that.

While having the red wagon project car headliner replaced, I inquired about reupholstering the seats.  The shop could do it for a reasonable price and it would look good, so I was told.

So months later when I was ready to fix this white sedan leather seat, I removed the seat and took it to the same shop for re-covering.  To save a lot of money we went with vinyl material.

Matched the color and texture as best we could and I left the seat there for a few days.  They removed the damaged seat cushion and seat back front leather and replaced those pieces with vinyl, leaving the original leather on sides and backs of seat.  It was stitched in place to look like original.

I was very pleased with the results.  Looks very nice and only a slight color variance.

New vinyl seat covers look great.

New vinyl seat faces look great.

Vinyl seat back re-covered to match leather.

Seat back re-covered with vinyl to match leather.

 

Shop even repaired the torn foam seat cushion.

Shop even repaired the torn foam seat cushion.

Slight color mismatch is not bad and looks better in sunlight.

Slight color mismatch is not bad and looks closer in sunlight.

Re-covered seat installed in car matches rest of leather seats well.

Re-covered seat installed in car matches rest of leather seats well.

View from passenger side.

View from passenger side.

My only complaint is that the vinyl is not as smooth as the leather when sliding into the car so my large posterior catches a little.  It may wear smooth over time.

Long-term durability is unknown at this point but I really doubt this car will go another 10-15 years anyway.

$180 vinyl replacement of leather panels.

#91 Replace Leaky Heater Core / Window Fogging

March 2, 2014

As mentioned in task #87, while checking for coolant leaks I discovered that the heater core was leaking.  I fixed the bigger leak at the upper radiator hose and left this heater leak for later.  It seemed just a minor nuisance where I could keep topping off the coolant level, plus my impression was that replacing the heater core was a big job.

Since then I’ve come to realize that replacement isn’t terribly difficult or time-consuming.  More importantly, I learned the hard way that a leaking heater core can be a real safety issue because it will fog up the windows.

This is a very common problem on 850s– probably on every car from the factory because of a poor design in the heater core itself where the plastic frame is not properly bonded to the heat exchanger.  After ten years or so (and all Volvo 850s are now at least 16 years old) the heater core will leak a little coolant.  Not too much, but enough to be a situation that needs attention.

Even if you are willing to just keep topping off the coolant, it’s a real problem because if you ever use your heater a leaky core creates a fine aerosol of coolant (water and antifreeze) which deposits a moist, oily film on the windows.

Leaking heater core puts a moisty, oily film on inside of windows.

Leaking heater core puts a moist, oily film on inside of windows.

This then attracts dust and such in the cabin which just obscures the windows even more.  Eventually it’s hard to see out the windows, particularly at night and when the sun is low.  Poor visibility is a real safety issue and is what convinced me I needed to fix the leak.  It took several passes with cleaner and rags to get the windows really clean and there is a lot of glass on a wagon.  This film is also being deposited on the passengers and everything else in the cabin.  :(

You will probably first detect a heater core coolant leak with your nose.  When any heat is turned on some air flows around the heater core and the vapor from the anti-freeze chemical moves into the cabin.  Most of us recognize the unique sweet odor of ethylene glycol in the coolant.  If you’re not sure, just remove the coolant reservoir cap and give it a sniff.  If you smell the same odor inside the car with heat on, you’ve got a leak.

Confirmation of a leak is coupled with an observable drop in coolant level in the reservoir.  The heater core is located forward of the transmission/gear shift lever under the dash just above the floor.  Access requires removal of the dash board lower covers and then pulling back carpet and removal of plastic covers under that.

When I opened up the panels on this car, I found a wet spot on the inside of one of the panels and shiny wet spots around the base of the heater box.

Obvious wet spots around and under heater housing.

Obvious wet spots around and under heater housing.

IPD has a great video showing the replacement procedure:  https://www.youtube.com/watch?v=cD7L9hzHtNo     It is for a 1998-2000 V70 so isn’t exact but only a few details are different.

MVS has a really good step-by-step procedure written up:  http://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=40547

General procedure to replace the heater core:

1. Remove lower dash covers on both driver and passenger sides.

Remove dash lower covers.

Remove dash lower covers.

2. Peel carpet against center console back on both sides.

Carpet pulled back.

Carpet pulled back.

3. Remove black plastic panel behind carpet to access heater box.

Black plastic cover removed.

Black plastic cover removed.

Coolant leakage is very obvious.

Coolant leakage is very obvious.

4. Unscrew core frame from heater box, two screws on each side.

Shop manual shows two screw locations.

Shop manual shows screw locations.

Access to these screws is somewhat awkward.  It helps to push the seats back, put a cushion on the floor, lay on your back working up and have a good work light.

5. Pinch off both heater hoses on engine side of fire wall to prevent draining engine coolant into the car.

Pinch off both hoses between engine and heater box.

Both hoses between engine and heater box pinched off.

Hose access improved by removing heat hose to air cleaner.

Hose access improved by removing heat duct to air cleaner.

6. Pull evaporator drain fitting out of hole to provide space for removing the heater box.

AC evaporator drain tube pulled up and out of way.

AC evaporator drain tube pulled up and out of way.

7. Unscrew tubes from heater box.

Single screw secures tubes to heater core.

Single screw secures tubes to heater core.

8. Pull heater core and tube block apart.  Be prepared with rags or towels for quite a bit of coolant leakage (residual in the hoses and tubes plus inside core).  It may take some prying and effort to separate.

Separate core from heater tubes.

Separate core from heater tubes.

9. Rotate heater box back and out the RH side (US passenger).

Rotate core out of heater box and out passenger side.

Rotate core out of heater box and out passenger side.

Note access to the heater box may be slightly different on earlier model 850s but the general idea is the same.  On models with manual transmission there is also a gear shift cable passing under the heater core to work around.

Heater core is now out of the car and can be worked on in a convenient location.

Heater core is now out of the car and can be worked on in a convenient location.

10. Remove screws holding the heater core in the frame and pull the old core out.

Four screws on end hold core in frame.

Four screws on end hold core in frame.

Core removed from frame.

Core removed from frame.

Wet spots at top (and bottom) of core typical of plastic separation from aluminum tubes.

Wet spots at top (and bottom) of core typical result of plastic separation from aluminum tubes.

Now ready to install new heater core.  While many people insist on using factory heater core replacements, the design is still flawed and will happen again.  They are also a bit expensive.  I chose to go with an after-market part that claimed to have an improved design.  It also comes with two new O-rings for sealing the tubes and is at a very good price on eBay.  This is likely a knock-off of a better part but they claim that their design fixes the expansion problem by crimping the tubes onto the plastic tanks.  If it lasts five years or more I’ll be happy; not sure how much life the car has left in it.

New core at right is an exact match to old one on left.

New core at right is an exact match to old one on left.

New core crimps tubes to plastic to avoid separation problem.

New core crimps tubes to plastic to avoid separation problem.

This new core came with foam strips installed.  If yours doesn’t, you would have install new foam strips to match old core.

11. Clean up the frame to remove oil and dirt.  Disintegrating foam strip leaves a lot of debris behind.  It also would not be sealing well, meaning some air flow through the heater box will bypass the heater core, reducing heat efficiency.  New foam will seal better and give better heating.

Old core foam strip was disintegrating and really gummed up the frame.

Old core foam strip was disintegrating and really gummed up the frame.

Cleaned up core frame before installing new part.

Cleaned up core frame before installing new part.

12. Put new heater core in frame and screw in place.

New and improved heater core installed in frame.

New and improved heater core installed in frame.

13. Remove O-rings from ends of tubes from firewall and replace with new ones.  If your tubes are corroded they should be cleaned up before installing O-rings.  If your pipes are steel (older models) consider replacing with newer aluminum tubes.  Always use new O-rings because the old ones will be dry, hard and not pliable.

Old, dry and hardened O-rings were removed.

Old, dry and hardened O-rings were removed.

Tube ends were slightly corroded.  Cleaned up the surface with strip of emery paper.

Tube ends were slightly corroded. Cleaned up the surface with strip of emery paper.

New O-rings installed with a bit of petroleum jelly.

New O-rings installed with a bit of petroleum jelly to improve seal and preserve elasticity.

14. Maneuver heater box back in place and push onto tubes to mate properly.  Screw core onto tube block to secure.

Core positioned in heater box.

Core positioned in heater box.

Pushed tubes into core to mate.

Pushed tubes into core to mate.

Screw core back onto tube block.

Screw core back onto tube block.

15. Screw core frame back into heater box on both sides, making sure the rubber seal is in place all around the seam.

16. Remove clamps pinching off heater hoses.

Don't forget to unclamp heater hoses!

Don’t forget to unclamp heater hoses!

17. Start the car and check for fresh leaks.  Shouldn’t be any with new O-rings.

No leaks with engine running!  This is an important check before buttoning things up.

No leaks with engine running! This is an important check before buttoning things up.

18. Top off the coolant level as needed, depending on how much was lost in this process.

Added fresh coolant to replace what was lost (about half a tank).

Added fresh coolant to replace what was lost (about half a tank).

19. Reconnect evaporator drain.

20. Install plastic panels on both sides of heater box.  Note the white plastic tab on heater core frame mates with slot in black plastic panel.

Replace plastic panels.

Replace plastic panels.

21. Push carpet back into place on both sides.  It’s probably a good idea to let the car air out for several hours (windows open) to evaporate much of the spilled coolant from inside the cabin.

22. Install lower dash panels.

I’m going to wait a week or two before cleaning the inside windows again.  There is likely some residual coolant in the ducts and air vents which has yet to be pushed into the cabin.  Once it’s dried out we can clean the windows for good.

Now I get to do this again on my 850 sedan which also has a heater core leak, just not as bad (no coolant loss and no foggy windows but antifreeze odor with heater on).

$39 for low-cost “improved” design heater core

Technical Note

The heater core is essentially a small radiator, much like the big one in front of the engine.  Hot coolant from the running engine flows through the core and air flows through the fins where the heat from the coolant is transferred to the air.

On Volvo 850s coolant flows constantly through the heater core; there is no shut off valve or regulator.  Heat into the cabin is determined by temperature settings on the climate control.  This regulates air damper position to direct more air through the heater core as you increase temperature.  So while hot coolant is always circulating through the heater core, it does not exchange heat to the cabin until the operator selects some heat.

Easy Cup Holder

March 2, 2014

I’ve been driving this red wagon project car to work while my 850 sedan is having the driver’s seat re-covered.

Besides having an automatic transmission on the wagon (which makes for a little confusion), another difference I noticed is the lack of a better cup holder.  I have a simple cup holder added to my sedan that accommodates a larger cup in a better location and I miss having this feature while commuting in the morning, breakfast smoothie in hand.

So I picked one up and added it to this car and the girls will probably appreciate it in the future as well.  Not worthy of a numbered task but thought I’d share this idea with others since it’s probably a common complaint about this car.

The stock 850 has only two useful cup holders which pull out in the center console.

Stock pull-out cup holders are small and obscure window controls.

Stock pull-out cup holders are small and obscure window controls.

They provide for only smaller cups and they are in the way of the window and mirror controls.

Years ago I discovered that one of these large cup holders with hooks works well on the console forward of the gear selector.  They are designed to hang from the door at the window but on 850s that surface is too wide for these cup holders to attach.

If you hang it on the side of the console on the passenger side, the driver can still reach it and it stays put as long as the ashtray is open.  The ashtray keeps the holder from bouncing loose or moving out of place easily.

Large cup holder hangs off console, held in place by open ashtray.

Large cup holder hangs off console, held in place by open ashtray.

On the driver’s side it would likely get kicked too much.  If you really wanted it to be secure, you could put a screw through it into the plastic console but that would leave a hole.

$0.62 for cheap plastic cup holder.

Keyless Entry (Remote/Key Fob) Programming

February 23, 2014

If your 850 has the keyless entry feature which allows you to lock and unlock the doors from a short distance using a small transmitter on the key chain (fob), here is the procedure for programming the car to respond to the remote control.

This is valid for Volvo 850 in model years 1996 and 1997 that use the remote/key fob shown below.  I have seen one reference that it applies to 1995 cars as well, so you really need to make sure you know what you have.  For earlier 850s there is a different remote but the procedure seems to be the same.

Volvo 9442982 Key Fob

Volvo 9442982 Transmitter

1.  Gather all the transmitters (key fobs) you want the car to recognize and keep them handy in the car with you.  You can program up to four remotes per car.  Make sure they have fresh batteries or are known to work.

2.  Start by sitting in the driver’s seat with doors closed (and from experience, tail gate closed and doors locked  on wagons.)  If it’s hot and uncomfortable inside, you can roll the windows down for some relief.

3.  Insert key into the ignition switch and quickly switch back and forth between positions 0 (off) and II (not III which will start engine) as quickly as you can five times.
Ignition Off     Ignition On

4.  Red light on top of dash pad near windshield should blink on and off with key still in position II.
LED

5.  Quickly push either button on each remote that you want the car to learn.  You have around 10 seconds per remote for this teaching input.  Light will glow steady for a couple of seconds when it recognizes a transmitter.

6.  Switch key back to 0 (off) and remove key.

7.  Test each remote function by unlocking and locking to verify they were all learned.

Repeat as needed if something doesn’t work quite right or if you were too slow.

Procedure from the 1997 Volvo 850 Owners Manual

Programming a transmitter

If you purchase additional transmitters (max. 4), they must be programmed to function with your alarm/remote keyless entry system. To do this:

  • Make sure all doors, hood and trunk/tailgate are closed.
  • Turn the ignition on and off 5 times within 10 seconds. On the fifth try, leave the ignition on.
  • Press either button on the transmitter.
    NOTE: The first transmitter must be programmed within 15 seconds, the others within 10 second intervals. When the alarm system accepts the codes from each transmitter, the LED on the dash will glow steadily for several seconds.
  • Switch the ignition off and test the transmitter(s).

Practical range of the remote transmitter is 10-15 feet (3-5 meters) per owners manual.  I have observed slightly greater range but it’s not a long distance.

Replacement transmitters are found on eBay in the $40-70 range used and $80-100 range for new.  Factory new part from volvopartswebstore is around $82.

If your 850 does not have this keyless entry feature but you’d like to have it, I posted an entry on retrofitting it quite easily at fairly low cost.

#90 Adding Keyless Entry, Part 1

February 23, 2014

I have been spoiled with my daily driver, an 850 sedan that has keyless entry.  This allows me to lock and unlock the doors from a short distance with a small transmitter that is attached to the key ring (remote key fob).  So when I drive this 850 wagon project car it’s a constant adjustment to think, “Oh, I have to put the key in the door lock and turn it–which way again?”

This made me wonder how easy (or hard) it would be to retrofit keyless entry to this car or any other 850 lacking the feature.  Turns out, it’s quite easy.  The wiring is all there, only a few components are missing.  At the very least, all you have to do is remove an immobilizer jumper relay and insert an alarm relay to make it work.

Looking at the difference between the cars, I see that this red wagon has a brown 210 relay while the white sedan has a gray double 210/211 relay.

Brown 210 single relay is just a jumper to bypass immobilizer when alarm relay is not installed.

Brown 210 single relay is just a jumper to bypass immobilizer when alarm relay is not installed.

Gray 210/211 double relay adds keyless entry and alarm feature.

Gray 210/211 double relay adds keyless entry and alarm feature.

To prove the theory, I removed the alarm relay from my sedan and installed it into the wagon.  Then tested the key fob remote control and the locks popped up and down like they should.  So then I knew it was just a matter of putting another one of these relays in the red wagon and programming it.

On 1997 models the relay is located under the (USA) driver’s side panel, tucked up above the hood (bonnet) release lever.  Three screws to remove and this panel drops out.

Remove access panel below steering wheel to locate alarm relay.

Remove access panel below steering wheel to locate alarm relay.

Pulled a couple of these 210/211 gray alarm relays from wrecks at a salvage yard months ago when we first started this project, thinking they would be useful some day.  That day has arrived.

Alarm relay is also the keyless entry receiver to activate door locks when the remote buttons are pushed.

Alarm relay is also the keyless entry receiver to activate door locks when the remote buttons are pushed.

Installed one in this project car by pulling the single brown 210 relay and inserting the double 210/211 relay.  The 211 side fills a socket that is empty without the alarm relay.

To retrofit keyless entry, simply unplug the brown 210 relay and install the gray 210/211 double relay in its place.  The 211 side fills a socket that is empty without the alarm relay.

To retrofit keyless entry, simply unplug the brown 210 relay and install the gray 210/211 double relay in its place.

Plugging the relay in is awkward and somewhat difficult working up in that tight space and having to contort your body just to get your arms in the right position.  There is also a fat bundle of wires right in the way that you have to work around/through.  But with a little fussing and practice, it’s not so bad.

To program the new relay to the desired remote transmitter, you turn the ignition switch (key) from positions I to II five times rapidly, then press the lock button on the desired remotes (up to three), then turn key off.  Doors must be closed and locked for this to happen.  A more detailed post on this procedure is found in the next blog entry.

The remote/key fob transmitter is Volvo part number 9442982 and looks like this:

Volvo 9442982 Key Fob

Volvo 9442982 Key Fob

For now I will use the two remotes we have that work on the sedan (both fobs will work on both cars) but may get one or two used on eBay for the girls to have for their own at a later date.

Part 2 of this retrofit will involve adding an alarm indicator to the dashboard and an alarm horn under the hood.  Neither are necessary for keyless entry but the red LED is nice to have for programming as well as a deterrent to would-be thieves.  The alarm siren is also nice to scare off somebody who breaks in and as an attention getter using the remote key fob panic feature.

Note: On older model 850s the receiver/alarm relay is a different box in a different location, I believe.  From what I gather, it’s a flat black package mounted behind the glove box liner to one side.  I don’t know if a retrofit is as simple for older models but I would not be surprised if it worked much the same, just different packaging and location.

$5 for alarm relay from salvage yard.

#89 Starter Replacement

February 20, 2014

Summary: Intermittent events where engine would not crank became more frequent and finally the starter quit working altogether.  Diagnosed by eliminating likely causes (battery, battery cables, neutral switch) and then tested by applying voltage directly to starter control terminal.  Finding the starter dead, it was removed and replaced.

Details:  Recently we experienced several instances where the engine would not start.  Turning the key to the start position resulted in just a clicking sound from under the hood but the starter would not turn.  Sometimes it would work and sometimes not so once again it’s a frustrating intermittent problem.

1st thing to check when the car won’t start is the battery condition because this is the main cause of starting problems.  Connected my analyzer and the battery checked out 100% perfect (voltage and capacity).

Then looked at battery terminal connections which were tight and clean.  This is the 2nd most common cause of starting problems.  Followed the fat red battery positive terminal wire down to the starter and it was tight and clean, as was the fat blue negative wire to the engine block.

The 3rd most likely cause of no-crank problems is a clutch switch (manual transmission) or Park-Neutral Position (PNP) switch (automatic transmission) being open.  850s do not have clutch switches from what I can tell; they were added to later model S70s, I believe.  This car has an automatic transmission so it does have a PNP switch which is known to fail with age.  Running the shifter up and down to freshen up the switch contacts did not help.  Besides, I could hear the starter solenoid clicking which indicates that it made it past these interlocks.

A 4th possibility is a defective ignition switch but that was replaced in the past year and as mentioned the solenoid was clicking, indicating that the circuit was working.

A 5th cause of starting problems is arguably more or less likely than the others.  This is the immobilizer or alarm relay which is an anti-theft feature that prevents the car from starting if the doors are not properly opened with a key or keyless remote.  It was not an issue here.

Once I got it to start more frequently I noticed that there was a delay from when I turned the key to when the starter would crank.  That indicates a sluggish starter solenoid, as if it was weak.  Then I noticed that after releasing the ignition key from start position the starter would stay engaged for a half second or so (that whirring sound you hear when  you are still cranking the starter after the engine starts running on its own).  That also suggested a lazy solenoid or weak return spring or sticky solenoid plunger, all of which are starter problems.

All these diagnoses point to the starter itself so I started testing it.  One nice thing Volvo did with the 850 (and likely other models) is include a handy starter diagnostic connector up near the brake master cylinder.  This female blade socket makes direct connection to the starter solenoid control terminal which receives +12V when the key is turned to the start position.

Starter test port location

Starter test port 17/1 location.

Test port near ignition coil and LH strut tower.

Test port near ignition coil and LH strut tower.

Actually, not quite a direct path.  The test connector still goes through the PNP switch on cars with automatic transmission after this point so if you want direct connection to the starter solenoid, you’d have to connect at the solenoid.  Manual transmission does go directly there.  See wiring diagram for details.

Wiring Diagram

Wiring Diagram

I made up a test wire by crimping some wire to a standard 1/4″ male blade terminal.  The male tab mates nicely with the test socket and gives us a handy connection to measure resistance (old starter solenoid measured high at 3.2Ω, new solenoid was 0.5Ω), voltage or apply voltage.  Instead of touching the other end of the wire to the battery positive terminal, I clipped a squeeze switch in line to get better control.

Test wire connected.  Far end connected directly to battery + or through switch makes starter operate as if turning they key.

Test wire connected. Far end connected directly to battery + or through switch makes starter operate as if turning they key.

Using the switch allows me to work without an assistant to turn the key and with the first pair of quick switches the starter would crank but then the starter stopped turning and I would hear a metallic clunk when activating the switch.  After several of these, I could get just a small click from the solenoid.  So clearly the solenoid and/or the starter were failing quickly.

Access to the wiring terminals is made behind the snap-on cover.  Be very careful with metallic tools down there; a short to anything metal will give full battery energy spark.

Pull this cover off to access starter terminals.  No tools needed; just snaps on/off.

Pull this cover off to access starter terminals. No tools needed; just snaps on/off.

Unplugged the control (start) terminal and measured voltage with respect to the engine block.  When energizing the test port I measured +12.5V so I know the starter is getting proper control voltage.  That clears up any doubt that the solenoid or motor were bad.

Measured control voltage at the disconnected wiring terminal.  +12V here with not start means a bad starter or solenoid.

Measured control voltage at the disconnected wiring terminal. +12V here with no start means a bad starter or solenoid.

Tried tapping on the solenoid and starter to see if this would make it work again.  Don’t laugh, this often gets a failed starter to work one or two more times if something is stuck or if the motor is in a dead spot.  No good and so now the intermittent problem has become a permanent problem.  Clearly the solenoid or starter motor has issues and the whole thing needs to be replaced.

Replacing the starter is not difficult but you do have to remove several things to gain access.

First you disconnect the battery negative (-) terminal after verifying you have the radio code.  Then you remove the control module cooling pipe, air duct to air cleaner, fan shroud assembly and relays and vacuum valves mounted to it, which requires disconnecting various cables and hoses.  Finally remove throttle pulley cover and solenoid cover if not already done.

Various air ducts and throttle cover removed for access.

Various air ducts and throttle cover removed for access.

Fan assembly removed for access to starter.

Fan assembly and associated wires and hoses removed for access to starter.

Now we can remove the starter itself.  Start by unbolting or unplugging all wires from the starter.

Cables disconnected from starter solenoid.

Cables disconnected from starter solenoid.

Then remove three bolts holding the starter to the engine block and lift the starter out. Shop manual and other procedures do not mention unfastening this harness clamp…

Harness clamp must be removed to get wrench on lower bolt.

Harness clamp must be removed to get wrench on lower bolt.

…or removing the throttle body intake pipe, but both had to be done for access.

Upper bolt can't be reached without removing the throttle body inlet pipe.

Upper bolt can’t be reached without removing the throttle body inlet pipe.

Once these three bolts are removed, the starter should just lift out.  If it’s really frozen in place it might take some careful prying but this one came free easily.

Starter should simply lift up and out once the three bolts are removed.

Starter should simply lift up and out once the three bolts are removed.

The mounting bracket on the left is separate from the starter so needs to be unbolted from the starter for use with the new part.

Bracket needs to be unbolted from the old starter...

Bracket needs to be unbolted from the old starter…

...and transferred to the new starter.

…and transferred to the new starter.

Note the photos shown are for a 1997 model 850.  Older 850s may have a slightly different starter as noted in the factory manual.

Note also this locator pin which hopefully stays with the starter.  If it sticks to the engine you will want to pull it out; new starter should come with a pin.

Locator pin engages with hole in engine housing.

Locator pin engages with hole in engine housing.

Rare peek at engine flywheel which engages with starter pinion gear to crank engine.

Rare peek at engine flywheel which engages with starter pinion gear to crank engine.

Tried to unscrew the solenoid from the starter to inspect the guts but could remove only one of three screws, even using an impact driver after spraying penetrating oil, so gave up on doing an autopsy.  Wish I knew what was going on inside there.

While many people insist on factory parts only, like several other tasks on this project I choose to save money by using a high-quality re-manufactured starter.

Shiny new starter.

Shiny new starter.

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I’m saving hundreds of dollars and I doubt that the quality difference will be noticeable in the short term.  Maybe 15 years out but I don’t think this car will still be around that long.  Besides, my experience with reman parts is that they often are factory parts that have been cleaned, renewed and tested so are as good as new.  This one had the Bosch ID stamps on it so is likely mostly factory parts.

As for the solenoid, I believe that there are two coils: one higher current (lower resistance) to pull the plunger in and one lower current (higher resistance) to hold the plunger in after disconnecting the high-current coil.  Since the old bad coil measured 3.2Ω and the new one measured 0.5Ω, I’m guessing that the high current coil was open or the disconnect switch was stuck open.  Either way, it would leave only the holding coil in the circuit which is not strong enough to pull the solenoid closed, at least reliably.

New starter is installed in reverse of the removal procedure.

New starter bolted in place...

New starter bolted in place…

...and wires attached.

…and wires attached.

Put all the ducts, fan, hoses, relays and covers back in place and ready to check after reconnecting the battery negative terminal.  Key in and it starts right up.  No surprise.

$140 for an remanufactured starter.

Technical Notes

The main parts of a starter are the motor and the solenoid which are combined in one assembly.  The motor is just a high-torque, high-current DC motor that is strong enough to spin the engine.

The solenoid does two important jobs and is often the culprit with a bad starter.  First it switches the battery connection to the motor winding, like a big high-current relay or contactor.  Second it pushes the pinion gear out to engage the engine flywheel teeth so that the spinning motor is coupled to the engine for starting and releases it once the engine is running.  These two things are accomplished in one linear motion by an electromagnetic field from the solenoid coil.

Fuel Pump Nut, Old/Non-Factory Gaskets and Petroleum Jelly

February 16, 2014

This is sort of an appendage to post #82 regarding fuel pump replacement.  There are three issues that I feel worth sharing with other DIYers.

First is that when you remove the fuel pump for replacement or rebuilding, it is important to thread the big plastic pump retaining nut back on the tank unless you quickly put the pump back in and secure it.  For whatever reason the male threads on the tank (Volvo calls it the collar) tend to expand or swell so that it’s hard to thread the locking ring back on if it has been off for some time.  I learned this the hard way when replacing the pump on this car in post #82 where I rebuilt the pump which took some time.  Since the nut was off the tank for some hours, I had a really difficult time getting it back on later.  The Volvo shop manual, Alldata DIY and the Haynes manual all have notes about doing this.

Second is to consider your fuel pump gasket when removing the fuel pump.  In one case where I replaced the fuel pump in my 850 sedan with a high-quality aftermarket pump, it came with a new gasket (rubber seal between the pump flange and tank). However, that aftermarket gasket was slightly under-sized so it would not stay in place on the tank rim and it would leak vapors because the sealing surfaces were not aligned.  Since then it has caused small–and sometimes large–evap leak codes.  When I installed a new Volvo factory gasket, it sealed properly and the leak went away.  I presume the same could happen with an old, dried gasket.  All the references indicate to use a fresh new gasket.

Third is that cheap petroleum jelly from a drug store is recommended to lubricate the new gasket to keep it pliable and give a better seal.  I had used plumber’s silicone grease which may be OK but petroleum jelly makes more sense.  I mean, hey– it’s petroleum based and we’re using petroleum fuel here.  Also recommended for the push-on fuel fittings for the fuel pump.  I dry swab the inside of the fittings and smear jelly on the metal connectors of the fuel tank.  This gives a better vapor seal, renews old dried O-rings and makes pushing the fittings on a little easier.  Now that I think about it, jelly would be good to apply to the fuel filter fittings as well since they have the same push-on O-ring seals.

#88 Coolant Temperature Sensor/Engine Stalling

February 8, 2014

Long post so I’ll give an executive summary first:  Occasional random events of engine quitting while driving caused me to narrow down possibilities.  Focused on coolant temperature sensor and learned that a loose connection here can cause surging and stalling.  Discovered that the sensor was aged and out of spec so needed to be replaced.  More importantly, the connector had major issues.  Replaced the temp sensor and replaced the connector contacts for reliability plus added a missing connector bracket.  Hoping this cures the engine stalling problem.

Now for the details:  For months now we have experienced the nuisance of having the engine just die while driving slowly.  It occurs infrequently and these intermittent problems are the worst kind to solve.  So far it seems to happen at half throttle; not at idle and not at highway speed.  No error codes on the ECU but when the engine quits the instrument cluster lights up with all those warning lights.  No real self-diagnostics to use here.  Car will usually start right up after these incidents.

Idle stalling problems are often caused by a dirty throttle body or a gummed up idle air controller but this is not a problem at idle.  In 850s stalls are frequently due to fuel delivery problems (fuel pump, fuel filter, pump relay.)  However, the pump was recently rebuilt, the filter is less than one year old and the relay was renewed so these are unlikely causes.  Ignition (spark) is also suspect although this is more likely to throw an error code which we are not seeing.

I was leaning towards an intermittent sensor to explain this problem.  Two sensors are used by the ECU to adjust fuel injection into the cylinders based on various conditions.  First is the mass air flow (MAF) sensor.  This one was new when we got the car and it seems to behave normally.  The other is the engine coolant temperature (ECT) sensor.  This one seems to be original and is turning colors with corrosion plus these are known to fail with age, coolant quality and overheating incidents.

The ECT sensor is sort of hiding under the upper radiator hose at the thermostat housing.

ECT sensor located at thermostat housing under upper radiator hose.

ECT sensor located at thermostat housing under upper radiator hose.

Looks a bit crusty now and has been there a long time.  Some people recommend they be replaced with the thermostat although I have never done so.  Flaky sensors are known to cause various problems from hard starts to poor fuel economy to mystery stalls such as we are experiencing now.  At any rate, since these are known to be problematic and this one is apparently old (likely factory original), I started investigating it.

There are resistance and voltage specifications for a proper functioning ECT sensor.  It is basically nothing more than a two-terminal resistor which changes value corresponding to temperature.  See tech notes below for details.  I unplugged it to check the cold resistance and was surprised to discover that the connector on the wiring harness side was broken and falling apart.  The two contacts were loose and not being retained in the connector housing.  The contacts were also fairly corroded.  I know that poor electrical contacts can cause all sorts of problems, particularly intermittent failures where they work most of the time but occasionally lose contact.  So this automatically became my main suspect for the stalling problem.

Socket contacts loose and corroded are a huge problem.

Socket contacts loose and corroded are a huge problem.

Sensor pin contacts properly retained in housing but also corroded.

Sensor pin contacts properly retained in housing but also corroded.

I suspect that the sensor signal cuts out intermittently with vibration while driving, which is interpreted by the ECU as a cold engine, which responds by dumping more fuel into the intake to a warm engine.  That gush of fuel effectively chokes the engine and it dies.  This was confirmed experimentally by running the engine, then while pulling the connector apart, the engine would suddenly surge a few times.  When plugging back together again, the engine died, just like the problem we are experiencing (although this experiment was at idle).  So the theory that a bad ECT sensor can cause the engine to surge and/or stall is proven true.  No error codes occur so it may be that intermittent contact is short enough to cause a surge but not long enough to register an error.

Cold resistance was measured with a multimeter and showed about 5200Ω.  Compared against a new sensor which measured 2400Ω and the sensor in my 850 sedan which measured 3000Ω, this cold value is quite high.  Factory spec is 2800Ω at 68°F (it was slightly warmer than this so the new part was right on spec). Ran the engine up to stable temp on the instrument gauge and checked the resistance at this level.  Measured 300Ω compared to my sedan at 200Ω and subsequent reading of 212Ω with the new sensor installed.  Factory spec is 150Ω at boiling, which we are just under so the value should be in the 150-200 range.  This old sensor is about twice the resistance it should be at both hot and cold.

I also have a nice code reader which will display the real-time data stream of monitored parameters.  This old sensor runs hot and stable at 180°F compared to my sedan at 200°F; not too far off but seems a little low, which is consistent with its higher resistance.

Data stream coolant temp parameter stabilizes at °F.

Data stream coolant temp parameter stabilizes at 180°F.

All these diagnoses lead to two conclusions:  First, the ECT sensor is old and high in resistance and operating values.  Second, the bad connector is quite likely causing intermittent connections to the sensor due to corrosion and unsecure terminals.  This intermittent connection can cause surges and/or stalling engines so both the sensor and the connector need to be replaced.

To remove the old sensor requires that the radiator be partially drained of coolant, then the thermostat housing removed for access to the sensor itself.

Coolant partially drained and thermostat removed for access to ECT sensor.

Coolant partially drained and thermostat housing removed for access to ECT sensor.

Unscrewing the ECT is a pain because there is no room for a standard 19mm wrench.  Factory procedure is to release the pin contacts from the connector to allow the cable to pass through a box-end (ring) wrench.  Polarity of the wires does not matter so there is no need to orient them when finished if this is done.

Sensor connector removed to allow box end wrench to slide over wires.  You could also just snip the wires if you're throwing the sensor away.

Sensor connector removed to allow box end wrench to slide over wires. You could also just snip the wires if you’re throwing the sensor away.

A bit tricky to remove connector housing.  Basically pry out on sides to release latch then flip end up.  Hinged near middle of connector.

A bit tricky to remove connector housing. Basically pry out on sides to release latch then flip end up. Hinged near middle of connector.

19mm box end wrench slips over wires to loosen/tighten sensor.

19mm box end wrench slips over wires to loosen/tighten sensor.

New sensor compared to old one.

Installed new sensor with fresh crush washer then secured the thermostat housing back in place and snapped the sensor connector back on the wires.  Polarity doesn’t matter (both wires are black).

New sensor installed with thermostat housing back and coolant refilled.

New sensor installed with thermostat housing back and coolant refilled.

Then added fresh coolant back in.

To repair the loose connector with corroded sockets I gave up trying to identify a new part number to order so went to a Volvo junkyard to snip one off of a scrapped 850.  But after looking at several, they all had some degree of corrosion and loose contacts so this is obviously a common problem that all 850 owners should be aware of.  I took the best connector I could find; the contacts were crusty but they were secure in the housing.

Old contacts are corroded and plastic bushing is hard and cracked so contacts are not secure.

Old contacts are corroded and plastic bushing is hard and cracked so contacts are not secure.

Found a website where a guy sells Volvo wire harnesses and connectors and relays and other interesting things.  Nothing specific to 850s but he sells connector bullet terminals with new bushings that are pre-crimped on 24″ wires.  Ordered a couple of these to try out and they fit fine in the old connector housing so I basically repaired the connector with new contacts by splicing them into the engine wiring harness.

Here are the female bullet contacts I ordered from Dave's Volvo Page.  Choice of colors.

Here are the female bullet contacts I ordered from Dave’s Volvo Page. Choice of colors.

Pre-crimped terminals fit perfectly in connector housing.

Pre-crimped terminals fit perfectly in connector housing.

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Verified good connection with sensor before installing either parts.

Verified good connection with sensor before installing either parts.

Solder spliced each wire into engine harness, then covered splice with heat shrink tubing before slipping wires back into split loom tubing.

Spliced new connector wires with solder joints covered by heat shrink tubing.

Spliced new connector wires with solder joints covered by heat shrink tubing.

Covered new wires with split loom tubing secured with cable ties.

Covered new wires with split loom tubing secured with cable ties.

This gives us a clean and secure connector to the sensor. This repair method can be used for many other connectors in the car.

Also installed a new retainer clip salvaged at the scrapyard to replace the one that was missing from this car.  Now this connector will be secured instead of swimming around on its own.

Installed missing connector retainer.

Installed missing connector retainer.

Plugged connectors together and secured on "new" retaining clip.

Plugged connectors together and secured on “new” retaining clip.

Sprayed contact cleaner on new sockets before plugging connectors together to fight off corrosion.

Ran the the engine to normal operating temperatures and verified that the sensor is behaving. Checked ECT with new sensor at normal running temp and it now reads 196°.

New sensor reads hot normal temperature of 198°F.

New sensor reads hot stable temperature of 196°F.  Was too low with old sensor.

Time will tell on this fix but I’m optimistic.  Assume it solved the problem unless I report otherwise.

$37.88 for a cheap after-market ECT sensor.  $10 for a sensor connector and retaining clip from a scrapped Volvo.

Technical Notes

The ECT sensor is a simple negative temperature coefficient thermistor.  That means its resistance decreases with temperature.

The Volvo 850 uses the known resistance curve to determine temperature proportional to this resistance based on the voltage across this sensor.  A pull-up resistor reference to +5V forms a voltage divider with the thermistor being the variable device.

ECT sensors are very important in the Volvo 850 (and most modern cars) because it is used for fuel trim, idle air, ignition timing and cooling fan operation.

ECT sensor resistance table per factory specs:

Resistance
7300 ohms at 32 deg F
2800 ohms at 68 deg F
1200 ohms at 104 deg F
300 ohms at 176 deg F
150 ohms at 212 deg F

From the factory functional description:

The Engine Coolant Temperature (ECT ) Sensor supplies the Engine Control Module (ECM ) with a signal describing the temperature of the engine coolant. This gives the engine coolant temperature (ECT) sensor a measurement of engine temperature and influences the control of:

  • Injection period
  • Idling speed
  • Engine Cooling Fan (FC )
  • Ignition timing
  • On-Board Diagnostic (OBD ) functions.

The sensor incorporates a temperature-sensitive resistance with a Negative Temperature Coefficient (NTC ). The sensor is supplied with a stabilized voltage of 5 V from the engine control module (ECM).

The voltage across the sensor is a function of the engine temperature and, therefore, of sensor resistance. Voltage can vary between 0 V and 5 V .

The engine control module (ECM) uses substitute values if the signal from the engine coolant temperature (ECT) sensor is missing or faulty, however, substitute values can cause starting problems in very cold weather.

The engine coolant temperature (ECT) sensor is mounted in the thermostat housing.

Evap Leak Detector (Fuel Vapor)

January 19, 2014

Had a recurring error code P0442 on my 850 sedan which indicates a small evaporative emissions leak.  This is often due to the fuel filler cap not being tightened.  In older cars with aged rubber it can be a cracked hose or elbow anywhere around the fuel tank or charcoal storage canister or evap purge valve.  When the crack is big enough you get the large leak code P0455.

Finding these is hard.  Professional shops often pressurize the fuel tank with some kind of non-incendiary smoke and look for where it might leak out.  I don’t have that specialized equipment and I’d be a little nervous with it anyway.  What I do have is a combustible gas detector that is rather sensitive.  It is made to check for leaks on natural gas (methane) appliances but the operating principle is such that it will detect any combustible gas, which includes gasoline vapors.

I have this UEI CD100A combustible gas leak detector.

I have this UEI CD100A combustible gas leak detector.

To prove the theory, I made a video showing it working as I crack open the fuel tank cap:

Capture

So you see how it can detect even small fuel vapor leaks.  The probe is long and flexible so you can snake it into small, narrow places if needed.  It doesn’t give an actual measurement but it will indicate a relative leak level.

Anyway, I used this technique to pinpoint a leak around the fuel pump.  Gasket was not located properly and nut was not tightened adequately.

This unit is around $134 on Amazon.  There are similar detectors on Amazon and generally on the internet.  You can pay as much as $400 for them but I don’t see any doing a better job than this cheap one.  It’s still a bit expensive but you can probably justify one if you have gas appliances in your home and you want to check for leaks periodically.  Factor in the hourly rate of dealer shops for something like this and it may pay for itself in the long run with an older car that will have fuel vapor leaks.

#87 Coolant Leak at Upper Radiator Hose

January 18, 2014

Car was losing coolant at a rate where the coolant level warning light would come on once a month or two.  Not a huge leak but concerned me enough to look into it before the situation got worse and maybe stranded the driver with a blown hose or overheated engine.

The leak was not enough to leave telltale drips on the ground so it wasn’t obvious what was leaking.  I also didn’t want to run the engine to get hot fluid circulating if I was looking for leaks.  The usual way to find a problem like this is to pressurize the cooling system with a special tester.  I researched this and found a decent one at Harbor Freight Tools for maybe $55 with a coupon.  Then I thought about rigging up my own tester to save money and thought I could get a new coolant reservoir cap and drill a hole in the old one and add an air pressure port to it and inflate with a bicycle tire pump or something.  That might work but then I noticed that the brake fluid reservoir on the 850 appeared to have a cap of the same size and thread as the coolant reservoir.  Those Swedish engineers are so clever!  It is the same fitting and so I could use my brake fluid pump to pressurize the cooling system.  Here it is connected to the coolant reservoir instead of the brake fluid reservoir where it is intended:

Motive Power brake bleeder pressure pump hooks up perfectly to the coolant reservoir.

Motive Products power brake bleeder hooks up perfectly to the coolant reservoir.

I checked the pressure relief rating of the coolant cap and it shows 150kPa which is about 22psi.

Coolant reservoir pressure cap relieves at 150KPA (20psi).

Coolant reservoir pressure cap relieves at 150kPa (22psi).

So I pumped the cooling system up to 15psi and looked for leaks.  Since there were leaks the pressure slowly dropped at a rate of about 5psi in 10 minutes (half psi per minute).

Pressurized cooling system to 15psi to make leaks more evident.

Pressurized cooling system to 15psi to make leaks more evident.

Checked around all hoses and fittings, the reservoir and radiator looking for signs of coolant.  Any cracks or weak points will leak fluid when pressurized.  I found a fresh wet spot below the upper radiator hose connection:

Small leak at upper radiator hose connection.

Small leak at upper radiator hose connection.

Hose seemed to be otherwise in decent condition so started by tightening the hose clamp.  I tightened it about two turns and then cleaned up the fresh coolant to see if that made a difference.

Sure enough, no more fresh coolant leaking and the pressure loss rate dropped significantly to maybe 1psi in 20 minutes.  That indicates there is still a tiny leak but this bigger one was taken care of.  I expect the hoses will need to be replaced in a year or two but for now this should cut down quite a bit on the coolant loss.

Finding no other leaks under the hood I went looking for trouble under the passenger side of the dashboard where the heater core is located.  Sure enough, after removing the lower cover I found a wet rusty spot and then more wet spots when I pulled the carpet back and removed the console side cover.  This is consistent with the odor of antifreeze (ethylene glycol) when the heater is turned on (fortunately not often here in central Texas).

So that will be a separate topic because it’s a big project to replace the heater core.  I’ll decide if and when on this later.

$0  No cost repair! (at least for now, pending hose replacement and heater core).

Two New Problems to Tackle

January 14, 2014

Well, with all my good intentions of getting a few more maintenance tasks accomplished soon, the weather and short days have minimized my time to look into things.  This time of year it’s dark when I get home from work and often cold so weekends may be my only chance to get anything done.

Meanwhile, two new issues have cropped up which require more immediate attention (not to mention a recurring error code on my 850 sedan for an evap leak).

First is a mysterious coolant leak.  The coolant level seems to drop fairly quickly with no signs of leaks on the ground and no steam out the exhaust so this will take some work to identify the problem.  I hope it’s not an engine internal leak (head gasket) which would be most serious.  It could be the heater core because I know it has at least a pinhole leak (I can smell antifreeze when the heater is on, but this is infrequent so may not be the main problem.)  Hoping it’s just a cracked coolant bottle or radiator or hose which can be replaced fairly easily.  Small enough not to notice a drip under the car but big enough to lose a liter or two in a month.  Will report on this when I get it figured out.

Second is more troubling– intermittent engine stalling.  Engine just dies when driving slowly; fortunately this hasn’t happened at high speeds when it could get hazardous.  Car can usually be re-started right away.  This could be many things from fuel problems to engine sensors/controls to ignition coil.  Whatever it is, it’s intermittent and these are difficult to pin down and diagnose because you have to catch it in the act and there are many possibilities here.  Very random problem once a week or two.  Will also report on this.  I don’t expect a fuel problem because I already replaced the pump and filter and repaired the pump relay.

Excellent Reference for Common Problems With 850

December 30, 2013

Thought I’d share this excellent reference for Top 10 most common problems with the 850.

IPD published a list of the most common problems with this car model, presumably based on failure data.  They mention ten items but the comments are also very helpful because dozens of readers mention other common problems and remedies.

Top 10 Most Common Problems With Volvo 850

This should be interesting and useful to all Volvo 850 owners.  I agree with the list and the commenter’s additional high-failure items since I have seen many of these on this project car and my 850 sedan.

Hard Start After Short Run

December 30, 2013

Interesting thing happens to this car when the engine is run very briefly.  Scenario is to turn the cold engine on and move the car three to six feet (one or two meters), then quickly switch the car off.

This condition will sometimes result in it being very difficult to start the car next time.  That is, the starter cranks hard and there is spark and fuel but no ignition; the engine simply won’t run on its own.

The explanation I have found on the web somewhere (and can’t locate this nugget of info again) is that when you run the car very briefly from a cold start it doesn’t give the engine controller time to adjust fuel air mixture and dumps extra fuel into the cylinders.  So next time the engine tries to start the cylinders are already wet and you’re just adding more fuel.  With the mixture so rich the wet plugs can’t ignite the fuel.

The solution which was suggested and which has worked for me a couple of times is to be patient and crank the starter for quite awhile, perhaps two minutes.  Holding the throttle open with the accelerator pedal brings more air in and eventually the ratio will ignite and the engine starts to catch.  It will soon run on its own although rough for a minute until things settle out.  If your battery is weak in this condition you may need to use jumper cables from another car.

Car is Back Home For a While

December 16, 2013

Well, this project car is back home for some time.  Have hardly seen it since August when it went off to college.  Will be here until late spring or early summer as the college driver will be studying overseas for a term.

That means we can get some more tasks worked on and you should see a little more activity here in the coming months.

Weather is cold here and money is tight so I probably won’t do very many expensive things but between the two 850s in the driveway I have several items to tackle.

Stay tuned.

#86 Air Guide Replacement

September 30, 2013

There is a large plastic cover under the engine called an air guide.  Its purpose is to protect the engine and also to help direct air flow for optimal engine cooling.  This air guide is also known as the belly pan, splash pan, skid plate or lower engine cover.

Since many Volvos are missing this part, some people don’t think they need one, but Volvo put it there for a reason.  Not only does it help guide air through the radiator, it also keeps water, dirt, gravel, rocks, wood, road grime, and debris off critical engine components like the alternator and belts.

Sometimes the air guide is removed for service and not replaced.  Also because the 850 is so low to the ground in front, the air guide frequently scrapes against parking curbs and such.  Eventually this will shear the plastic hangers and the air guide falls off.  That’s what happened here.  If you’re fortunate you will notice this and rescue the part.  If the part is left behind you’ll need to get a new air guide, louver and clips.

Black tabs on left and right sides are all that secure the air guide to the car.  When the guide shears off you have just the mounting tabs bolted to the chassis.

Black tabs on left and right sides are all that secure the air guide to the car. When the guide shears off you have just the mounting tabs bolted to the chassis.

Broken tab on other side.

Broken tab on other side.

On this car we were able to recover the broken air guide so it was a simple matter of transferring the louver to the new air guide.

Old louver transferred to new air guide.

Old louver transferred to new air guide.

Old louver transferred to new air guide re-using mounting clips.

Old louver transferred to new air guide re-using side mounting clips.

New air guide with old louver ready to install on car.

New air guide with old louver ready to install on car.

While the air guide is secured to the car with bolts at the sides, there are features that help hold it in place loosely.  Without these installing the air guide is difficult.

A line of clips at the front holds the guide on top of the front bumper ledge:

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A slot at the bottom center of the radiator accepts the rear tab of the air guide:

Rear tab supported by slot in radiator.

Rear tab supported by slot in radiator.

Note that this radiator slot is frequently crushed by jacking or high curbs so may need some coaxing back into shape with pliers.

Supported in front on the bumper and back on the radiator, the air guide will stay in place where it can easily be secured with bolts at right and left:

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When done it looks like this:

New air guide installed.

New air guide installed.

The round hole nearest this view is for radiator draining.

The Volvo diagrams show an additional smaller air guide piece that fits in or around the open rectangle.  I have this part but haven’t figured out exactly how or where it goes because nothing makes sense with it.  This main part should be all you need to protect your engine and improve air flow.

$17.98 Factory Replacement Air Guide (note shipping for this large item may be expensive, although with Volvo Parts Webstore it was not)

Updates to Two Recent Posts

September 29, 2013

Not much activity lately as the car has been off to college since August.  Had it home this weekend so was able to check the oil level.  Favorable results to report with the thicker oil (15W-40) so I updated that post.

Also updated the post about lifting the car to add info and photos with ramps.

Hope to post at least one new entry in the near future.

Engine Oil Consumption, Type & Viscosity

July 21, 2013

Nothing will get a forum stirred up like a discussion of engine oil.  Lots of opinions on the topic, and many people strongly believe in certain types, brands and viscosities.

Regarding brand or type, I have no strong opinion and to split the difference between the synthetic oil vs. conventional oil crowds I went with a blend of the two at the posted oil change topic, and selected a name brand based on price and availability.  When not changing the oil myself I usually have it done at Firestone where they use their own conventional/synthetic blend.

5W-30 installed at oil change.

5W-30 installed at blog posted oil change.

Since then I have been mystified at the significant oil consumption of this car along with my daily driver, another 1997 Volvo 850 (sedan).  Decent power and no tailpipe smoking but they seem to lose a quart every 1000 miles or less.

Pondering this I started researching oil consumption and type and realized that the 5W-30 is a bad choice for the 850 in this climate.  Central Texas is relatively hot most of the year and rarely drops below freezing in winter.  5W-30 is intended for cold climates where normal oil will thicken at low temperatures.  Here is a chart from the 1997 Volvo 850 owner’s manual:

Owner's manual chart of viscosity range vs. ambient temperature.

Owner’s manual chart of viscosity range vs. ambient temperature.

It shows that the 5W-30 is fine for low temps (not needed here) but, worse, it is not recommended when used above 68°F (20°C) ambient, which we frequently exceed here.  The problem with the low temp rating in higher ambient conditions is that the chemicals needed to make the oil flow when cold break down and form sludge.  And as it breaks down there is less chemical to keep it thin at lower temps, so the cold rating becomes progressively weaker.

10W-30 would be a better choice, being commonly available, but even that is challenged by our high summer temps per the chart.  15W-40 seems ideal for my situation, based on min and max temperatures here.  It’s not very common (more of a diesel engine oil) but I can find it at Walmart and auto parts stores plus at least one of the oil change places says they have it.

15W-40 is actually on the chart of permitted viscosities but there is a note in the manual cautioning the low end temperature range:

Owner's manual note regarding unsuitable viscosities.

Owner’s manual note regarding unsuitable viscosities and 15W-40 usage.

Not a problem here so I will be switching over to 15W-40 shortly and see if oil consumption drops off.  Will add an update here as I learn if it helps or makes no difference in consumption.

Edit 29 September 2013:  After switching to 15W-40 on both 850s I can report favorable behavior results.  It’s been more than a month and oil consumption has dropped significantly.  No smoke from the exhaust and the engine runs fine.  Hardly notice the drop in oil level on the dipstick now where it was adding a quart every week or two before with thinner (5W-30) oil.

Tech Note

I’m no tribologist but I’ve done a bit of online research on this.  Viscosity is a fluid’s resistance to flow.  A single number (eg, SAE30) denotes oil viscosity at normal hot engine temperatures.  The smaller the number the more quickly it flows, meaning it is thinner.  Heavier oil flows more slowly and has a larger number.  Ultimately you want a viscosity that is optimal for the car’s engine at operating temperatures, which is typically SAE 30 or 40 for the model 850.

A number with a W (for winter, such as 10W) means is behaves like a an SAE 10 rated oil at a low temperature.  The lower the W number, the lower the temperature the oil will flow.  So colder climates need lower W numbers when the engines are started up to have some lubrication until they warm up.  These can be thought of as “thinner” oils until they get to engine operating temperatures when the second number becomes dominant.

The combination is called a multigrade oil and reveals the low temperature behavior and the normal high temperature behavior.  So 5W-30 is a thinner 5 viscosity when cold but heavier 30 viscosity when warm.

In warm climates the low W numbers are too thin for old, worn engines so they get consumed faster than higher W numbers.  I also expect that the older, worn engines can tolerate a higher warm viscosity as well, perhaps improving compression?

Some good references to viscosity I have found:

Motor Oil Viscosity Grades Explained in Layman’s Terms

What Does the Weight Mean on a Can of Oil?

More Than You Ever Wanted to Know About Motor Oil

How to Pick the Right Motor Oil

Car Maintenance Bibles: Oil Viscosity

Motor Oil 101

#85 ECU Air Duct

July 20, 2013

When the radiator shroud was removed to replace the front engine mount I noticed that the black plastic air duct which brings cooling air to the engine control unit (ECU) was cracked at the corrugated bellows.

Cracked air duct leaks air intended to cool ECU.

Cracked air duct leaks air intended to cool ECU.

This cracks leaks air so that the ECU will get less cooling, a concern here in the hot climate of central Texas.

The part itself is not very expensive (~$10) but why replace when it can be easily repaired at little or no cost?  The simple solution is to wrap black electrical tape around the cracked area.  The tape is flexible to allow for movement and it is durable– the same repair has lasted for several years on my other 850.

A few wraps of electrical tape make for a quick and easy repair that lasts for years.

A few wraps of electrical tape make for a quick and easy repair that lasts for years.

$Free, assuming you have a roll of electrical tape around the house.

Key Fob Repair

July 19, 2013

Some of our Volvo 850s have the optional remote keyless entry system installed which uses a small remote control typically attached to the car keys (key fob).  This particular remote style (Volvo part # 9442982) is used on 850s in years 1996 and 1997 (the last two years before becoming S70/V70) along with a few other Volvo model numbers.

One weakness in the design is the flexible strap from the remote control module to the key ring.  I have seen both leather and a vinyl-like plastic or rubber strip used for this and both will tear over time so they separate.  If it’s a clean tear near the remote you may be able to punch another hole in the strip and re-attach it to the remote.  After doing this a few times on three key fobs it became impossible to re-attach.  So I devised a simple way to connect the key ring without the strap.

Basically you disassemble the remote by first removing the batteries.  Then pry the two halves apart with a non-marring tool.  A guitar pick works well for this.

Prying the remote apart.  A guitar pick is very handy for this.

Prying the remote apart. A guitar pick is very handy for this.

Inside you can break it down into a printed circuit board (PCB), buzzer and then a rubber pushbutton membrane.  Taking all these out leaves you with the two black plastic halves of the remote housing.

What I do is carefully drill a hole in both halves where the strap retaining pin is (break the plastic post off first).  The hole should be just larger than the key ring you want to attach.  It can be fairly large before compromising the integrity of the plastic housing.

Holes drilled in each half of the remote.

Holes drilled in each half of the remote.

Then re-assemble the key fob with all the parts in place and slip the key ring through the hole.  It works well and you’ll never have them separate again.

Key fob ready for action again without breakable strap.

Key fob ready for action again without breakable strap.

While we’re on the subject, there is one more little hint here regarding the buzzer.  When you push the lock and unlock buttons there should be a slightly audible chirp from the remote.  This is audible feedback that the remote sent out a lock/unlock signal; basically telling you that the battery and pushbuttons are working.  If you don’t hear the chirp it means either that the remote is defective, the batteries are weak or dead, or that the buzzer is dislodged or otherwise does not have a good connection to the circuit board.

The buzzer touches two arms extending from the board and it sits in its own recess in the bottom half of the remote.  It should be oriented as shown.  If it doesn’t chirp with fresh batteries and is situated properly, the contacts may be corroded.  Try scrubbing the buzzer surface with a pencil eraser, along with the metal contacting it.  It should work with clean connections, fresh batteries and being properly installed.

Buzzer sits in pocket as shown with bi-metal ring facing this direction.

Buzzer sits in pocket as shown with bi-metal ring facing this direction (towards circuit board.)

Adding Content Not Specific to Project Car

July 19, 2013

We started this 1997 Volvo 850 wagon project a year and a half ago and so far the blog has exclusively detailed this particular car.  I have documented 84 maintenance or repair items to date plus thrown in several posts on general topics or non-repair items.  If it has a number, it is a repair or maintenance item.  No number means general topic or improvement task or something along these lines.

Interest in this blog has grown quite a bit and we have followers around the world.  In fact, this blog has really grown way beyond my original intent of letting my kids know what I’ve been doing to the car.  The truly interested audience now are hundreds of fellow 850 owners looking for encouragement, advice or reference.  If I can do it, you probably can, too.

Since we have tackled most of the main tasks on this project car, I think it’s time to start adding in a few things that I have done on my own daily driver, a 1997 850 sedan.  This car is slightly different but still an 850 and such posts would be very relevant to the blog.  Sure, there will still be several items in the future on the project car (it never ends, does it?) but don’t be surprised to see some posts featuring my other 850 now.

The other car in our stable.  You will see some posts involving this one in the future.

The other car in our driveway. You will see some posts involving this one in the future.

Besides the obvious color and body style differences they are much the same– age, mileage, normally aspirated (non-turbo).  Differences are: the sedan has a manual transmission, sun roof, beige interior with wood dash and leather seats (electric).  So for all practical intent, things that I do to the sedan could very well be tasks on the project car (in fact, many have been done to both cars.)  And adding this in the mix makes it more helpful and relevant to an international audience.

#84 Flasher Relay PM

July 13, 2013

This was a quick preventive maintenance task.  Over time the flasher circuit can go bad in these cars and the turn signals or emergency blinkers will not work.  This is sometimes due to a defective electrolytic capacitor in the flasher relay module located in the dash.  I have seen discussions on 850 forums where the turn signals stopped because of bad capacitors so I wanted to be proactive and refresh them on this car before they did cause trouble.

The flasher module is removed by prying it out of the dashboard.

Pry carefully on sides/top with narrow tool and pull flasher module out of dash, then unplug connector.

Pry carefully on sides/top with narrow tool and pull flasher module out of dash, then unplug connector.

To open the module the two lamps have to be removed first by twisting CCW.

Two lamps need to be removed before sliding board out of module.

Two lamps need to be removed before sliding board out of module.

Then the module is opened by prying up on both sides to free them from the locking tabs.  A thin, sturdy guitar pick is particularly useful for this and I keep a few handy for opening electronic cases and car modules.

Carefully pry up on housing on both sides to release inner module.  Guitar pick is particularly helpful.

Carefully pry up on housing on both sides to release inner module. Guitar pick is particularly helpful.

There are four electrolytic capacitors on the printed circuit board.  These are the four black cylinders shown.

Electrolytic capacitors are the four cylinder shapes on the PCB.  Rectangular object is the flasher relay which makes the clicking sound when it switches on and off.

Electrolytic capacitors are the four cylindrical shapes on the printed circuit board (PCB). Big rectangular object is the flasher relay which makes the clicking sound when it switches on and off.

Unsoldered all four capacitors and replaced with high quality replacements of same capacitance and voltage.  Capacitance value and tolerance are the most important thing, along with temperature rating.  It’s OK (actually, good) to replace with higher temperature and voltage ratings, but be aware that size increases with voltage rating.  Component spacing is also important but you can often force-fit a physically larger part with wider pin spacing onto a PCB if needed.

New capacitors installed with old original parts in background.  New parts slightly larger in size but fit with no problem.

New capacitors installed with old original parts in background. New parts slightly larger in size but fit with no problem.

After soldering in the new caps and clipping the leads I checked the circuit side for solder blobs or residue.  Cleaned with alcohol and brush then re-assembled module.  This is a good time to replace the two lamps, especially if one is out (the emergency flasher lamp probably has a lot of life left in it.)

Plugged the module back in the car and tested to make sure flashers and turn signals worked, then pushed the module back into the dash.  Ready for another 15 years, hopefully.

Several modules in the Volvo 850 have circuit boards with electrolytic capacitors and the caps can cause problems for any of these modules as they age.  For a detailed explanation of electrolytic capacitor function and failure, refer to the technical notes in item #54, fuel pump relay.  If you’re handy with a soldering iron it’s an easy and economical fix for some of these fairly expensive modules.

$1.57 for four capacitors.

#83 Front Engine Pad

July 8, 2013

Since we got this project car a year and a half ago it has bothered me that there is quite a bit of engine vibration in the car.  This was made worse when I replaced the upper torque mount and lower transmission mounts with long-lasting but stiff polyurethane parts.  At idle it’s not too bad but fairly strong when the automatic transmission is in the drive position (engine torque applied to wheels against brakes).  This suggests that there is some engine twist towards the front of the car, even after I pre-loaded (tightened) the upper torque mount while in the drive position.

The Volvo 850 engine rests on three separate engine mounts which are in turn sitting on the engine sub-frame.  There is a hard rubber mount below the crank pulley on the right hand side of the car, and this is a prime candidate for vibration when it wears down since it can allow the engine to directly touch the chassis.  However, this mount appears to be in good shape upon visual inspection and you would expect constant vibration if this one failed (when idling and in drive.)

Besides the rigid mount on the RH side there are two large fluid-filled pads in the middle of the engine, one forward and one aft.  Because these are filled with fluid they usually indicate failure by leaking their filling (some kind of hydraulic oil?)  Without this fluid they are just shells of rubber which provide only weak support to the engine.

I suspect that the engine pad in the front of the car is bad.  It’s not leaking but could have bled out years before we got the car.  It appears somewhat collapsed since the safety cable surrounding it is somewhat relaxed.

Suspect engine pad located behind the radiator.

Suspect engine pad located behind the radiator.

Replaced the front engine pad by unbolting it above and below, then lifting the engine with a jack to gain clearance to remove and replace the pad.  The upper torque mount and lower transmission mount  need to be removed to allow engine movement for this operation.  Also the fan shroud is removed to gain space to unbolt the mount top nut and remove the pad.

Fan shroud moved out of the way.

Fan shroud moved out of the way.

Engine pad upper nut removed easily with swivel spark plug socket.

Engine pad upper nut removed easily with swivel spark plug socket.  Starter solenoid cover just clips on/off; pull off for more clearance to nut.

Engine pad lower mount bolt needs to be removed but was actually missing on this car.

Engine pad lower mount bolt needs to be removed but was actually missing on this car.

Upper torque mount unbolted.

Upper torque mount unbolted front…

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…and rear.

Lower torque mount unbolted.

Lower torque mount unbolted.

Engine lifted up with jack pushing up on oil pan (using wood block to spread load and protect pan).

Engine lifted up with jack pushing up on oil pan (using wood block to spread load and protect pan).

Engine lifted enough to free pad/mount.

Engine lifted enough to free pad/mount.

Old pad loose, ready to remove.

Old pad loose, ready to remove.

Pad is fairly large.

Pad is fairly large.  Safety cable keeps top and bottom linked in case the rubber mount separates.

Comparing old and new pads.  Old pad slightly shorter and more impact was felt when struck against concrete.

Comparing old and new pads. Old pad slightly shorter and more impact was felt when struck against concrete.

New pad installed, top view.

New pad installed, side view.

After installing the new engine mount/pad, everything was put back together (torque mounts, fan shroud).

Fired the engine up and put the automatic transmission in drive with the brake on, the worst-case vibration situation.  Unfortunately there is still significant vibration.  It is slightly improved but I will need to look for the vibration problem somewhere else later– rear engine pad, hard mount, stiff torque mounts…

$63 New Front Engine Pad

Lifting the Car and Working Safely

July 7, 2013

This post is for my new friend Donovan in South Africa.  He made me realize that a basic task such as lifting the car is not obviously accomplished without the right equipment and instruction.

Much of the work done to the car is with wheels off or just to have clearance under the car to work.  Proper lifting and support techniques are essential to minimize the chance of bodily injury or damage to the car.

If you have nothing else to raise the car, the emergency jack stowed inside the spare tire is your only tool at hand.  This scissors-type jack is placed under a lift point and then the handle is cranked clockwise (CW) to raise the car and counter-clockwise (CCW) to lower it.  When using the emergency jack, only the pre-defined jack points should be used.  These are located in the body below the front doors, one on each side.  These points are determined to be optimal to lift one side (left or right) equally, front to back.  The locations are slightly forward of the mid-line since most of the weight is up front with the engine.  Follow the instructions in the owner’s manual for jack usage.

Emergency jack in low position, ready to lift car.

Emergency jack in low position, ready to lift car.

Jack raised to maximum height.

Jack raised to maximum height.

Lift point located for height roughly equal front to rear (car's weight distribution heavier to front).

Max lift equal front-rear.  Jack is strong but not terribly stable so use care with emergency jack.

When working on the car in your garage, the car’s jack should be used only if a better jack is not available.  This jack requires a lot of physical work and is not particularly stable.  It has only minimal point of contact to the ground and to the car and it is narrow, meaning it is prone to having the car slip off the jack and crashing down.

When working on the car for maintenance or repair (non-emergency), a good hydraulic floor jack is a necessity.  This type of jack is on wheels so it will automatically center under the lift point.  It also spreads the load out over a wider area for excellent stability and it requires minimal physical exertion when raising and lowering the car.

Two typical sizes of hydraulic floor jacks,  Small one rated for 3300 lbs with a 14" lift.  Large one rated for 4500 lbs with an 18" lift (most useful).

Two typical sizes of hydraulic floor jacks, Small one rated for 3300 lbs with a 14″ lift. Large one rated for 4500 lbs with an 18″ lift (most useful).

Jack located at same lift point as emergency jack.

Jack located at proper lift point.

Larger jack quickly gives good lift height.

Larger jack quickly gives good lift height.

Always support the car on stands after lifting with a jack.  That means after the jack stands are carefully placed in position, lower the car to rest on the stands.  After the car is resting on the stands, push the car hard with all your weight side to side AND front to back.  This force will verify that the car is stable on the stands and that wind, a bump or tool force will not push the car off the stands while you are working underneath it.

Jack stand placement must be on reasonably firm, level ground under a solid, stable part of the car.  For the front I use these points behind the wheels towards the centerline:

Good front jack stand location.

Good front jack stand location.

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For the rear I use a point inside the wheels:

Good rear jack stand location.

Good rear jack stand location.

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When working on one side only (such as when rotating the tires front-rear/rear-front), raise the car at the designated lift point, then place stands front and rear and lower the car onto them.

When working under the front of the car only, you can lift the front once and place jack stands under both sides.  A good lift point for a hydraulic jack is the front engine sub-frame, reasonably centered:

Front end lift point- engine sub-frame.

Front end lift point: engine sub-frame.

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When using the single front lift point you can quickly get to this good working arrangement:

Lifted onto jack stands and ready for front end work underneath.

Lifted onto jack stands and ready for front end work underneath.

When working on the rear only, there is not a good single lift point so you’re stuck lifting one side at a time for placing jack stands.

Another safety consideration is to make sure the parking brake is set and that the wheels are blocked opposite the end that is being lifted.  This prevents the car from shifting away from the jack and jack stands.  These curved wedges are ideal but you can use anything that practically prevents the tires from rolling:

Rear wheels chocked when front is lifted.

Both rear wheels chocked when front is lifted.

When working on the car with wheels on (oil change and under-engine work), ramps are another option.  You simply drive up them to ramp height and the ramps provide extra clearance under the car to work.  The down side to ramps on the 850 is that you need low-profile ramps to clear the low and long front end.  This means practical lift is only about 8″ (200mm) and the car is already under 8″ to begin with.  So with ramps you get less than 16″ (400mm) working room but this is manageable for most people, depending on the work and tool size/motion required.

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850 front end is rather low and long, requiring shallow ramps.

I find that most of my work is wheels-off so I need the jack and stands anyway.  But for oil changes and other wheels-on work ramps are convenient if you don’t need much clearance underneath.  Shown below are ramps in action for an oil change on my white sedan.

Low clearance ramps needed.

Low profile ramps needed.

Drive car up ramps after carfully positioning them.  Good to have a 2nd person to monitor when driving up.

Drive car up ramps after carefully positioning them.  Good to have a 2nd person to monitor when driving up.

Ramps provide reasonable room under car for working.

Ramps provide reasonable room under car for working.

#82 Fuel Pump Dead (Rebuild)

June 30, 2013

After running very low on fuel the car would not start.  The starter would crank and there was spark but the engine would not show any signs of ignition.  After adding a gallon of gas it still would not start.  I must have killed the pump by letting the fuel level drop too low since the electric pump sits in the bottom of the gas tank and is cooled by the liquid fuel.  One too many times, I guess, and this was the episode that finally did it in.

I verified that the problem was fuel-related by a lack of pressure at the fuel rail on top of the engine and certain that the fuel pump relay was working.  Further, I was able to temporarily get the pump running by banging on the fuel tank from under the car.  Sometimes if they fail you can whack them into submission but this is a temporary fix only; it will not last so the pump has to be replaced.

Fortunately the fuel pump can be replaced without removing the fuel tank.  There is an access plate inside the car (in the trunk/boot of Sedans and under the rear deck of wagons).  Once this cover is removed the pump can be replaced from inside the car.  Many of the same steps were involved in the fuel tank removal in item #57.

Fuel pump beneath a cover under the rear deck.

Fuel pump access beneath a cover under the rear deck.

Depressurized the fuel line (if the pump was fully dead there may not have been much pressure) at the Schrader valve near the fuel filter underneath.

Then disconnected the fuel lines by carefully prying up the slip-on fuel connectors (noted their position for re-connection).  Unplugged the fuel pump connector so the unit was free to remove.

Unscrewed the big plastic locking ring holding the fuel pump to the fuel tank.  This was done with large adjustable jaw oil filter pliers (the official Volvo method involves a special fuel pump spanner wrench.)

Oil filter pliers work well to turn the locking ring (giant plastic nut).

Oil filter pliers work well to turn the locking ring (giant plastic nut).

Note: At this point fuel can leak out of the tank, depending on how full it is.  If you just filled up and the tank is overflowing up the filler pipe you may want to siphon fuel down below the top of the tank.  The safest thing here would be to completely drain the fuel tank to minimize the hazard of fire or explosion.  Also disconnect the car battery to eliminate one source of ignition should fuel vapors accumulate.  Obviously, no smoking or open flames or sparky things while working with/around fuel.

After removing the locking ring, I lifted the pump out of the fuel tank and set aside to dry out for disposal or rebuilding.

Lifting the pump out of the fuel tank.

Lifting the pump out of the fuel tank.

Drying the pump out in the sun.

Drying the pump out in the sun.

I chose to rebuild the pump by replacing the pump component instead of replacing the whole pump assembly.  This is much more economical; I bought a complete fuel pump service kit from FCP which includes the pump, new locking ring, strainer, wiring harness, fuel hose, gasket, plus a fuel filter and even a new fuel pump relay (which is good to have as a spare but I did not replace it since I just rebuilt it).  All factory parts, not after market junk.

This took some time so while I was rebuilding the pump I covered the open fuel tank hole with aluminum foil to minimize vapors in the car on a hot day and reduce the chance of something falling down into the tank.

Covered the opening with foil while rebuilding the pump.

Covered the opening with foil while rebuilding the pump.

Update 4/9/14: As mentioned in a follow-up post, if the locking collar (nut) securing the pump is to be off for more than a half hour, thread it back on to the fuel tank.  This prevents swelling of the tank port which will make it difficult to put the nut back on later.

Rebuilt the pump assembly indoors (hot day so the air conditioned house was a blessing!) by replacing the pump component and a new strainer.  This involved separating the inner and outer housings and loosening the supply hose.

Pump assembly separated with old and new pumps shown.

New parts shown outside original pump assembly.

Assembly separated with old and new pumps for comparison.

Assembly separated with old and new pumps for comparison.

New pump is shorter and smaller diameter.  Foam sleeve around new pump makes it fit in housing.

New pump is shorter with smaller diameter. Foam sleeve around new pump makes it fit in housing.

New pump installed in lower housing, ready to re-assemble into upper housing.

New pump installed in lower housing, ready to re-assemble into upper housing.

Re-assembled rebuilt pump.  Female disconnect terminals match original pump and they are sized differently so no possibility of reverse polarity.

Re-assembled rebuilt pump. Female disconnect terminals match original pump and they are sized differently so no possibility of reverse polarity.

Replaced original gasket which was hardened and stiff with new one supplied with kit.  Added some silicone grease to gasket for better seal on top of tank.

Replaced original gasket which was hardened and stiff with new one supplied with kit. Added some silicone grease to gasket for better seal on top of tank.

Installed filter sock to bottom of pump in proper orientation.

Installed filter sock to bottom of pump in proper orientation.

Installed the renewed assembly back in the fuel tank with a new locking ring provided with kit.  Tightened locking ring just past hand tight.  Plugged wiring connector back in and pushed hose fittings back on.

Checked for leaks with engine running to make sure there were no surprises.  Then tested by driving the car at high speed to make sure the rebuilt pump was working well before I put the cover and decking back on.

Ran the car and then drove it before re-installing covers over pump.

Ran the car and then drove it before re-installing covers over pump.

Post-mortem exam revealed that the original pump motor had an open coil, consistent with overheating.  Good pump motor coil reads about 1.5 ohms on a multimeter; this one was infinite (open circuit).

Moral of the story here is:  To preserve the life of an in-tank fuel pump (on any car, not just the Volvo 850), don’t let the fuel level drop too low, at least not very often.  Lacking proper cooling from the gasoline can cause the pump motor to overheat and fail.  I have heard professional mechanics say you should re-fill when down to 1/3 tank; probably good advice.

$150, Complete fuel pump service kit from FCP

#81 Recirc Air Damper, Round 3

June 29, 2013

The car is back with me for a couple of weeks so I will try to get a few things done to it.  Problem now is outdoor temperatures here in central Texas.  We’re having a heat wave with temperatures over 105°F (41°C) so it’s miserable working on the car on the hot concrete driveway (no working room in the garage; it’s too narrow).

While driving the car home on a warm evening I observed that the recirculating air damper was not working, yet again :cry:.  Third time’s the charm!  I think I figured it out now.  And to many people this is not a big deal; when the arm breaks or becomes disconnected, gravity pulls the damper open for fresh air , which is usually not a problem.  But as mentioned in an earlier post, we really want recirculating air on two occasions: 1) When a bad odor is outside the car we can mostly block it out by closing the damper;  2) On hot days recirculating air comes out of the air conditioner even colder because you are cooling air which is cool already.

After replacing a broken damper arm (task 30), it worked for a while then the arm slipped off the motor and I re-attached it (task 67).  It slipped off again and this time after re-attaching I observed the arm motion very carefully.  I noticed that as the motor rotated the arm up and down it would drag on the motor housing and wobble, putting some side force on the arm, which eventually worked off the motor shaft.

Damper arm scraping against motor housing pushes arm off motor shaft over time.

Damper arm scraping against motor housing pushes arm off motor shaft over time.

To solve this I did two things:  First I smeared a bit of thread locking compound onto the motor shaft and inside the intermediate lever arm to help hold it in place more firmly.  Second when I re-attached the arm I did not push it all the way on so now there is little or no contact with the motor housing when it rotates.  This way it won’t drag and push the arm off the motor shaft.  To play it safe I also sprayed a little white grease on the motor housing where it would rub so there would be less stain on the motor gearbox if they do make contact.

Arm not pushed onto motor shaft as far prevents scraping.

Arm not pushed onto motor shaft as far prevents scraping.

While working on this I checked operation of the air conditioning today.  With a thermometer in the center vent on fan setting 3, I measured 105°F (41°C) blowing out with AC turned off.  With AC turned on it dropped down to a reasonable 60°F (16°C) for a 45° split.  Closing the recirculating air damper gained another 10°F drop, and that was idling in the driveway.  Temps should lower more when driving because more heat transfer will occur with more air flow through the condenser.  So the AC is holding up well for this hot summer.

$0

#80 Wheel Alignment

May 19, 2013

Whenever any parts are replaced (or even loosened) that attach to the wheel hub, the wheels should be aligned.  For the front wheels this includes the struts, tie rod ends and the control arms.  Wheel alignment should also be checked if there is unusual vibration or if the steering is pulling to one side.  Since I just replaced the control arms and tie rod ends and the previous owners obviously had struts replaced and the tires were wearing badly, it was time for wheel alignment, especially since we just put new tires up front.

Wheel alignment affects not only tire wear but front end vibration, steering and handling as well.  In general the driver will really notice the difference between bad alignment and good.  Alignment adjusts to factory specification of caster, camber and toe, which are the three possible variations in wheel position relative to the car’s frame.  Front end is most important and most likely to be off but a proper alignment checks and adjusts the rear wheels as needed.  Wheel alignment is a highly specialized measurement and adjustment process which requires expensive equipment.  There is very little the DIY person can do here apart from very gross, basic adjustment such as tie rod end position to affect steering wheel centering.

castercambertoe

Alignment gets thrown off factory specs over time as the car experiences jarring impacts to the suspension from potholes, speed bumps, curbs and such.  Ball joints also wear and settle in over time which further changes alignment.  Every car should have the alignment checked and adjusted periodically, especially if parts are replaced or the suspension has experienced violence.  Also when replacing struts, tie rod ends or control arms, these parts will wear in after time and need the alignment tweaked after several weeks or months of driving with the new parts.

I like Firestone shops for this because they offer a lifetime alignment service where you can take the car in many times to get checked.  As often as I work on these older 850s, it is money well spent.  Firestone provides a report of the before and after measurements and they did quite a bit of correction, even to the rear which I haven’t touched.  The car drives and steers nicely now.

$160 lifetime alignment

#79 New Front Tires

May 19, 2013

Rear tires were replaced some months back but while replacing the control arms and tie rod ends in the previous task (#78), I observed that the front tires were in fairly bad shape and needed replacement.

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There was some tread wear remaining but not too much.  Of concern was the irregular tread wear where the inside and outside edges are worn down.  This is often explained by tire pressure under-inflation but can also be attributed to poor wheel alignment as well as loose ball joints in tie rod ends and control arm.  We have tried to keep tire pressure set properly on this car so that doesn’t explain all the wear.  As noted in previous task, there was wear in the ball joints.

Also of concern is considerable cracking of the rubber:

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This is sometimes called dry rot and indicates an old, dry tire which is in danger of separating.  This is more prevalent in warmer climates such as we have in Texas.  At high speed it could mean a dangerous blowout so we want to get these replaced right away.

New tires installed to match rears so we are good for several years with four new shoes.

New shoes.

New shoes.

$158 (not premium performance tires, just good basic tires)

#78 Control Arms and Tie Rod Ends

May 19, 2013

Back when the drive axles were being replaced (#51) I observed that the tie rod end and control arm ball joint boots were in bad shape and that these parts needed to be replaced. Finally got around to replacing these parts at the same time since it was convenient to do so and report them as one task.

Outer tie rod ends link the inner tie rod ends from the steering gear to the steering knuckle on the wheel hubs.  They have a ball joint at the steering knuckle to allow the wheel to move up and down and pivot left/right.  This ball joint is lubricated and covered with a dust boot to keep grease in and dirt out.  When it tears or comes apart it lets grease out and dirt in, which will cause the joint to loosen and eventually fail.  The tie rod end joints were collapsed and torn and there was some play in the joint, indicating failure has begun.  Steering tightness and feel is affected by this joint as is tire wear.  The tie rod ends needed to be replaced.

After the wheels are removed the tie rod ends are pulled out by first loosening the jam nut , then unscrewing the nut on bottom of the steering knuckle and separating the stud from the wheel hub.  Separation can be done with a special tool or just a “pickle fork” joint wedge and hammer.  Tapping up on the stud from below also helps and is easier if you are replacing the tie rod end and don’t care if it is damaged with a hammer.

Tie rod end separated from wheel hub and jam nut loosened.

Tie rod end separated from wheel hub and jam nut loosened.

Now the tie rod end can be threaded off the inner tie rod end to remove it.  Count the number of turns so the new part can be positioned at the exact place (for proper steering/wheel alignment).

Outer tie rod end removed from steering gear (inner tie rod end).

Outer tie rod end removed from steering gear (inner tie rod end).

Old ball joint was loose and getting worse quickly; compare to new part.

Old ball joint was loose and getting worse quickly; compare to new part.

Installed new outer tie rod ends and tightened properly with new nut at steering knuckle.  Ready for control arm replacement.

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Control arms are A-shaped parts that connect to the chassis/sub-frame on the inside and support the bottom of the wheel hub on the outside.  They provide stability and support to the front wheel and are an important factor in handling and wheel alignment.

Like the outer tie rod ends, the control arms also have a ball joint attached to the front wheel hub.  Older model 850s have a ball joint which can be replaced separately but on later models such as this 1997 car the ball joint is permanently attached and the whole control arm has to be replaced.  As with the tie rod ends, these ball joints had torn boots and were worn, as evidenced by some play.  Time to replace them.

Control arms are attached with two bolts at the sub-frame and one bolt tightening a spherical clamp at bottom of the wheel hub.  Note that the bolt must be removed (not just loosened) to free the ball joint at the wheel hub.  The joint may also need to be coaxed out with a joint separation tool or pickle fork.

Control arm removed from RH side.

Control arm removed from RH side.

Old and new control arms for comparison.

Old and new control arms for comparison.

Old boot was collapsed and ball joint was worn.

Old boot was collapsed and torn and the ball joint was worn.

Installed new control arm using new fasteners provided with kit, tightened to specification.  Note that two bolts at sub-frame are installed finger-tight at first before wheels are installed.  Final tightening of these two bolts is done at nominal at-rest position on wheels (pre-load).

View from below of new control arm installed.

View from below of new control arm installed.  White shape is steering stop bumper.

Sub-frame mounting bolts installed finger-tight only until car is resting on wheels.

Sub-frame mounting bolts installed finger-tight only until car is resting on wheels.

Tie rod ends and control arms replaced on both sides of car.  LH side shown here.

Tie rod ends and control arms replaced on both sides of car. LH side shown here.

Final tightening of the control arm sub-frame bolts is done with car resting on wheels in two stages.  First is tightening to a certain torque value, then an additional 120° (two hex bolt corners).  This is very difficult to do with the wheels in place.  Some people measure the resting distance to the fender and then lift the wheel hub up with a jack to the same distance, which does not obstruct the bolts.  I used another method which requires an assortment of socket extensions and a U-joint attachment.  The forward bolts are easy to access but the rear-most ones are difficult.  By turning the wheel so that there is an opening forward, you can get a socket wrench in there:

U-joint and extensions allow large wrench clearance to tighten bolts.

U-joint and extensions allow large wrench clearance to tighten bolts while…

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…backing wrench on nut tightens itself against tire to keep it from turning while torquing the bolts.

Edit 8/14/2013: FCP has an excellent video showing control arm replacement on 850s:  FCP Control Arm Replacement  They do final tightening of the control arm sub-frame bolts with the wheel off but jacked up to neutral resting position.  This is a good idea but you need to measure the height against a reference point on the frame (fender wheel well, for example) to know how high to jack the wheel hub.

Car needs wheel alignment work when these parts are loosened or replaced.  Did this in #80.  With new tie rod ends and control arms the car handles better; it steers more tightly (feels less sloppy) and seems more confident.  Alignment helped, of course, but I’m sure these parts made a difference as well.

$160 for high quality Meyle tie rod end and control arm kit.

Technical Notes

Final tightening of the control arm sub-frame bolts should be done when the car is in its neutral resting position on the wheels.  This pre-load torquing is important to minimize the twisting shear forces on the rubber bushings.  As the control arm will pivot up and down with the wheels as the suspension moves vertically, the bushings will twist with the arm.  If the bushings are tightened with the wheels off, the arm is in an unnaturally low position.  When resting on wheels the bushings would always be twisted and then move further when the car ran over bumps.  This wears out the bushings or, worse, can actually shear them.  So the bolts must be tightened (pre-loaded) at the most neutral position where they would normally not see any or much shear force.

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Ball joint play or looseness can be grossly determined by lifting the car and then moving the wheel.  When the wheel is rocked side to side, movement indicates tie rod end joint play which requires replacement.

Any movement side to side indicates tie rod end ball joint looseness.

Any movement side to side indicates tie rod end ball joint looseness.

When the wheel is moved pushed top and bottom, movement indicates control arm ball joint play which requires replacement.

Any movement top to bottom indicates control arm ball joint looseness.

Any movement top to bottom indicates control arm ball joint looseness.

#77 Side Door Trim Buckling

March 31, 2013

Here’s another nuisance trim problem that is common to these cars.  The ends of the side door trim molding are secured to the door with double sided adhesive tape.  Over many years the tape can come loose where the end of the trim will pull away from the surface.  Then when the door is opened the end of the trim jams against the sheet metal in front of it and buckles the molding out of shape and the door won’t open fully.

Buckled door trim prevents door from opening fully.

Buckled door trim prevents door from opening fully.

Ideally I would have replaced the trim molding but they are expensive and the color may not match the rest of the car.  So I straightened the trim out flat as best I could in place and then secured the end back down with silicone adhesive.  Clamped the end against the door with the front door propped open while the glue set.  Turned off the door open light to prevent battery drain while the door stayed open.   Cleaned it up a bit so it looks OK now.  Not as lovely as a new part but passable and cheap.

Two clamps hold trim in place while adhesive cures.

Two clamps hold trim in place while adhesive cures.

After straightening and gluing end of trim back on.

After straightening and gluing end of trim back on.

I could have done a better job if I had removed the strip and flattened it on the garage floor, then applied adhesive more precisely.  However, I had little time and the result is good enough.

If you notice your trim coming loose at the ends, re-secure it before you buckle the trim. It’s a lot easier to do before it’s damaged and looks better.

$0

#76 Roof Trim Peeling

March 31, 2013

The metal trim on the side of the windshield that continues on to the back of the car along the roof line is coated with a dark gray plastic material. The coating cracks and starts to peel off due to heat, age, chemicals and UV radiation.  In this case, a large piece was very loose and made a racket from turbulence when the car was driving.  Daughter temporarily secured with duct tape until the car came home for Easter weekend for me to deal with.

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Tape held coating in place to prevent loud vibration when driving.

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This coating rarely lasts 10 years so all Volvo 850 owners have had to deal with this by now.  There are three typical solutions to this problem.  First is to replace the roof trim with new parts.  They are hard to come by and expensive when you can find them ($180 each side).  Salvage parts are unlikely to last long since time and environment are the enemy here, if you can find any that are still intact.

The next easiest thing to do is to remove all the plastic coating and just leave the trim with the metal finish.  Changes the look but it’s not the worst thing.  Some people actually like it this way.  Sanding the trim smooth and shiny improves the look.

What most people seem to do is to remove the old coating and finish it smooth, then recoat or paint the strips to look more like the original.  For now I just removed the coating with a utility knife but plan to sand and then apply a dark gray bumper coating spray when I have more time.

Removed coating carefully using utility knife.

Removed coating carefully using utility knife.

All coating removed; looks OK but I will re-coat later.

All coating removed; looks OK but I will re-coat later.

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Both sides were coming apart so removed coating on passenger (RH) side as well.

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Roof trim coating comes off of all 850s after 10 years. Sedans have a lot more exposed trim without the roof rack on the wagon.

$0

#75 New Headliner

March 15, 2013

Here is the second item not done at home; windshield replacement was the only other item we paid to have done professionally so far.

As mentioned way back in #11, the headliner was a big problem sagging badly.  I temporarily tacked it up using special headliner screw pins and it has held up for over a year now.  But this temporary arrangement was unattractive and there has been a persistent odor that I suspect is trapped in the fabric and foam backing in the headliner so it was time to replace it.

DSCN7662

Headliner temporarily tacked up using special pins.

The upholstery shop carefully removed dozens of screws, molding and other fasteners to remove the entire headliner.  On wagons this is a fairly large piece.  Fortunately this project car does not have a sun roof which would have made the job more complicated.

Then they stripped the old fabric and foam backing from the structural headliner fiberboard.  New foam was then glued on followed by fabric to match what was removed.  The headliner was re-installed in the car and secured as before with all the fasteners and molding and such.

DSCN2383

New headliner looks and smells great now.

DSCN2385

DSCN2387

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Looks great now and smells better in the car.  Once the glue odor dissipates it should be very pleasant.

This is a potential DIY job but it is fairly involved.  You can buy kits which include new fabric, foam and adhesive.  You still have to remove the headliner board which can take a couple of hours figuring out and risk breaking aged fragile plastic clips.  For the price I felt it was worth having a professional do the work.  One specialty headliner shop did not even accept the job because the car was too old and they worry about breaking plastic clips and such.

$173 at a discount upholstery shop

#74 Slow Front Oxygen (O2) Sensor, Code P0133

March 9, 2013

An old, slow oxygen (O2) sensor was indicated with a check engine light (CEL) and error code P0133.

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There are two oxygen sensors in this car, one that does most of the work in front of the catalytic converter (Bank 1 Sensor 1).  The rear is mounted just after the cat and it serves to validate the front readings and monitor catalytic converter performance by comparison.

Oxygen sensors can last a long time but after 100K miles or 10 years they can’t be expected to keep going and are recommended to be replaced even if they are not misbehaving.  At 16 years old and 160K miles this sensor is long overdue.  The front O2 sensor is largely responsible for an optimal fuel/air ratio so often replacing an old sensor improves fuel economy.  Will have to see if that is the case here.

Since the front sensor is the critical one and these are expensive parts, I replaced only the front O2 sensor.  This is fairly easy if you know what you are doing but lacking instruction I wasted a lot of time figuring out how to unplug the sensor connector from the wiring harness.

Start from above by unplugging the O2 sensor being replaced and unclipping the sensor cable from the frame.

Sensor plug is unlocked by prying the red connector latch up.

Sensor plug is unlocked by prying the red connector latch up.

The front O2 sensor is on the left towards the middle of the car.  The rear sensor is on the right, which I did not deal with here.  Reportedly the two sensors are keyed differently so it is impossible to reverse connect them.

Raise the car and secure on jackstands to work from underneath.  Finish unclipping the sensor cable so it is free to the sensor.

Front sensor is located just in front of the catalytic converter after the exhaust manifold.  Spray penetrating oil around the O2 sensor fitting for easier removal.

Penetrating lubricant helps free the tight sensor.  Note wiring clip removed from frame.

Penetrating lubricant helps free the tight sensor. Note wiring clip removed from frame.

Break the sensor free from the exhaust pipe.  A special 22mm (7/8″) O2 sensor wrench is helpful here but not required.  Once it’s loose the sensor can be screwed out by hand.

Special O2 sensor socket maximizes grip on seized fittings.

Special O2 sensor socket maximizes grip on seized fittings.

Compare old and new sensors.  The new one has anti-seize lubricant on the threads already.  Used an exact Bosch replacement part.  Generic or universal sensors are known to have troublesome wiring problems or be unreliable.

Old and new sensor.

Old and new sensor.

Close up comparison of old and new sensors.

Close up comparison of old and new sensors.

New sensor installed and tightened in using special socket wrench.

New sensor installed.

New sensor installed and cable secured to frame below.

Sensor cable reattached to frame and plugged back into the harness.

Sensor cable secured to frame above and plugged into connector (Automatic Transmission).

Sensor cable secured to frame above and plugged into connector (Automatic Transmission).

Sensor cable secured to frame above and plugged into connector.

Sensor cable secured to frame above and plugged into connector (Manual Transmission).

Lower car back onto its wheels and it’s ready to roll.  Reset the error code and hope it doesn’t come back.  It hasn’t reared its ugly head again and the O2 monitor has finally gone ready.

By age and miles the rear O2 sensor should also be replaced at the same time but it is less critical and the monitor is not complaining about it and they are expensive so will wait until the ECM throws P codes about the rear sensor before replacing it.

$152 new front O2 sensor

Technical Notes:

Trouble Code Conditions

  • The engine control module (ECM) continuously monitors the time (period 3.3 seconds) it takes for the HO2S to switch from rich to lean and back to rich again. If this time is too long, the engine control module interprets this as a fault in the front heated oxygen sensor (HO2S) and diagnostic trouble code (DTC) EFI-435 is stored (P0133).
  • Before fuel trim starts the front heated oxygen sensor (HO2S) must be ready – it should be at operational temperature and have the correct output voltage. Monitoring of the heated oxygen sensor function starts approx. 3 minutes after heated oxygen sensor heating starts. Diagnostic trouble code (DTC) EFI-212 is stored if there is a fault in the front (P0130, P0131, P0132,P0135) or rear (P0136, P0137, P0138, P0140, P0141) heated oxygen sensors or their cabling that affects the output voltage from the front heated oxygen sensor.

Function
The heated oxygen sensor (HO2S) only operates above certain temperature , approx. 285°C . Normal operating temperature is in the range 350 – 850°C .
The heated oxygen sensor (HO2S) is heated electrically. One terminal is supplied with 12 V by the main relay, while a second terminal is connected to the engine control module (ECM). When this terminal is grounded, a current flows through the PTC resistor in the heated oxygen sensor (HO2S).
When the heated oxygen sensor (HO2S) is cold, the value of the PTC resistance is low and the current in the circuit is high. The engine control module (ECM) pulses the current initially to prevent damage to the PTC resistor. The resistance increases and the current falls and becomes continuous as the temperature rises. The heating period is short, approx. 30 seconds.
The heated oxygen sensor (HO2S) can be damaged if it is exposed to condensed moisture from the engine while the device is hot.
Heating of the heated oxygen sensor (HO2S) starts immediately the engine is started. When sensor temperature reaches 350°C it is maintained at a constant level until exhaust gas temperature at the front heated oxygen sensor (HO2S) and catalytic converter temperature at the rear heated oxygen sensor (HO2S) are high. This is to ensure that the temperature around the sensors is high enough to avoid water condensing onto them.
Both heated oxygen sensor (HO2S) terminals are connected to the engine control module (ECM).
When the engine is running rich, the oxygen content of the exhaust gases is low or zero. The heated oxygen sensor (HO2S) is then transmitting an output voltage of approx. 0.9 V .
When the engine is running lean, there is an excess of oxygen in the exhaust gases. The output voltage from the heated oxygen sensor (HO2S) almost drops to 0 V .
The change from high to low signal level occurs at the ideal (stoichiometric) air/fuel ratio of 14.7 kg air/1 kg fuel.
The engine control module (ECM) continuously uses the heated oxygen sensor (HO2S) signal to control fuel injection so as to maintain the ideal air/fuel ratio of 14.7 kg air/1 kg fuel.

#73 Secondary Air System Fault / Vacuum Leak / P0410

March 8, 2013

The check engine light (CEL) came on so I plugged in my handy OBD2 code reader and learned that the car was complaining about the secondary air injection system with code P0410. Secondary air system (SAS) is an emissions control feature that pushes air into the exhaust to increase catalyst heating and to help burn up hydrocarbons and carbon monoxide.

SAS faults are common on Volvo 850s and I have spent a lot of time working on it in my 850 sedan.  Not sure if all model 850s have this feature or just certain North American cars, but it seems to be widespread in the USA at least.  Of course this cropped up shortly before the car’s annual state inspection was due and I had to get it happy before then.

This time the fix was very simple: an aged, cracked vacuum elbow at the secondary air system (SAS) valve was leaking so that the SAS valve would not open properly.

Leaky vacuum elbow.

Leaky vacuum elbow at SAS valve.

Elbow replaced; no leak now.

Elbow replaced; no leak now.

I replaced this vacuum elbow and all other vacuum line couplers in the SAS system.  While the others were not in such bad shape they were degrading and would have failed eventually.  The elbow at the SAS valve is particularly subject to stress since it vibrates constantly when the engine is running.

Replaced both elbows at SAS control solenoid valve.

Replaced both elbows at SAS control solenoid valve.

Replaced elbow at vacuum supply (intake manifold tree).

Replaced elbow at vacuum supply (intake manifold tree).

Replaced both vacuum line couplers to vacuum check valve.

Replaced both vacuum line couplers to vacuum check valve.

Reset the monitor and the problem went away and has stayed away.

Others have worked out a technical fix to fool the engine controller into thinking the SAS is working when in fact the pump is not running.  In locales where environmental regulations are more relaxed this may be OK but I have observed that it may affect the oxygen sensors and cause other problems or reduced O2 sensor life.  So I chose to keep the SAS running normally on both my cars.

From what I can determine, SAS operation is monitored indirectly by the oxygen sensor in front of the catalytic converter.  When operating at cold start (rich exhaust), the air injected into the exhaust system burns residual fuel so the O2 sensor will see a relatively lean condition. If it doesn’t see lean exhaust after several attempts it assumes the secondary air system isn’t working and sets the CEL with P0410 code.

Some SAS details:

The major components in the SAS are the air pump, air pump relay, SAS valve and the SAS switching solenoid valve.  Any or all of these can be defective and cause SAS issues.  In fact, on my other 850 all four parts had to be repaired or replaced.  Besides these major players the vacuum tubing, elbows and check valve can also cause problems, as we saw here.

The SAS valve attaches to a tube from the exhaust manifold.  The big hose from the air pump pushes air into the exhaust when the controller pulls a vacuum on the control tube.  Older SAS valves tend to stick open so that even when shut off by the controller they allow exhaust gases to pass down to the air pump.  This valve was redesigned years ago to close more reliably but can still stick open.  A stuck valve can kill the air pump by allowing hot exhaust gases into the pump which condense and corrode the innards.  A valve which won’t open (frozen or lacking full control vacuum) will result in the P0410 error code.

The SAS solenoid valve switches the vacuum from the intake manifold to the SAS valve when an electrical signal is seen from the engine control module (ECM).  If the valve fails to switch you will get a P0410 fault.  If the solenoid coil opens up or the connector is unplugged, you will get a P0412 code.  This is located above the radiator fan below the shroud.

The air pump pulls air from the intake and pushes it into the exhaust manifold through a [supposedly] open SAS valve.  Common failures of the air pump are when the SAS valve sticks open and allows corrosive moisture into the pump which will seize up.  The air pump is situated below the battery shelf.  Access for testing or work is accomplished either above or below.  From above you need to remove the battery and battery tray.  From below you need only remove the splash guard from underneath the engine.  I find it easier to get to it below but you are working upwards while laying on your back to do this.

The air pump relay switches the high-powered pump motor on and off with a low level signal from the ECM.  Newer 850 models have the relay attached to the pump while older models have the relay mounted nearby.  Relays can fail or have connection problems which cause the air pump to not operate.

$11 vacuum elbow kit

Technical Notes:

The secondary air system reduces the emission of hydrocarbons (HC) and carbon monoxide (CO) and heats the catalytic converter more rapidly after cold starting. When the engine is started from cold the SAS introduces fresh air (~20% oxygen) into the exhaust manifold in order to promote after-burning (oxidation) of hydrocarbons and carbon monoxide. This makes it possible to increase the injection period and retard ignition, increasing exhaust temperature and activating the catalytic converter more quickly.

The system consists of:

  • Air injection pump (1) activated via the pump relay (2). The air pump takes fresh air directly from the air cleaner housing to avoid introducing dirt and water into the system.
  • The secondary air system (SAS) valve (3) with its built-in check valve prevents exhaust gases being forced into the air pump.
  • A solenoid valve (4) which controls the SAS valve using the negative pressure (vacuum) from the intake manifold.
  • A check valve (5) to maintain maximum negative pressure.

The Motronic 4.4 MFI controls the pump relay and solenoid valve using separate outputs from the engine control module (ECM). The SAS is activated 20 seconds after the engine is started if engine temperature is between -12°C and +35°C. After that the system remains active for 60-100 seconds depending on engine temperature. If car speed is below 10 km/h after 20 seconds, only the SAS valve is activated. The air pump only starts when car speed exceeds 10 km/h and operates until the SAS valve is deactivated, regardless of whether car speed drops below 10 km/h.

The air pump starts when the SAS is being diagnosed (at least 10 minutes after the engine is started).

SAS

Service Light Reset

December 23, 2012

The engine control module knows what mileage is on the vehicle and turns on a service light at certain intervals to remind the driver that the car should be taken to a shop for periodic maintenance.

DSCN2331

This nag light stays on for two minutes after the engine has started so that it doesn’t mask a more urgent check engine light which the driver may miss otherwise (just to the left of this light).

Those of us who are doing our own work on these cars rarely have them in the shop where they could reset the service light.  Unfortunately this year (1997 model 850) requires a very specific tool to reset the light; it cannot be accomplished using a wire jumper or pushbutton sequence like many other cars.   I’ve read stories from other owners who cover the light with black electrical tape or even remove the lamp from the instrument cluster to make this go away.

If you are a hard-core DIYer and want to do it right, you can buy a Draper 69007 service reset device online for less than $100.

Other devices may exist to reset the 850’s service light but this is the only one I am aware of that works for sure.  This unit works on model years 1996, 1997 and 1998 (when the name changed to S70/V70), I believe.

Service light reset device.

Service light reset device.

Draper model 69007

Draper model 69007

Only dip switch position 3 should be on for 1997 model 850.

Only dip switch position 3 should be on for 1997 model 850.

Plugs into OBD2 port under coin holder cover below ash tray.

Plugs into OBD2 port under coin holder cover below ash tray.

 

 

#72 Headlights

November 24, 2012

One of the headlights was out and the lamp needed to be replaced.  This is a routine maintenance item on all cars but there are many different types of lamps and methods of access.

On this vehicle the lamps are replaced by unscrewing the round cover from the back side of the headlight assembly.

Circular back cover removed.

Twist lamp CCW to free and pull out of holder.

The wiring harness plugs directly into the lamp with a connector.

Installation of new lamp is reverse order.  Always use gloves when handling the lamp!  Never let your skin touch the glass bulb.  See tech note below.

Detailed instructions are found in the owner’s manual.

I wanted to have extra-high-brightness lamps for the girl’s safety while driving through wildlife-rich countryside at night.  So ponied up for these expensive Sylvania Silver Star Ultra lamps which claim to provide 50% more brightness than ordinary 9006 lamps.  They advertise up to 40% increased down-road visibility and to improve side-road (peripheral) visibility by approximately 50%.

These high-performance low beam lamps are very bright.

These high-performance low beam lamps are very bright.

Lamps should always be replaced in L/R pairs so they are equally bright, even if only one has gone bad.

Repaired cracked wiring in previous post (#71).

$46 for two high-performance lamps type 9006

Technical Notes:

Bright lamps such as used for headlights operate at very high temperatures.  Any natural body oils from bare skin will remain on the quartz bulb and cause an extra hot spot which will cause the envelope to fail quickly.  Always wear clean gloves when handling halogen lamps.  If you accidentally get oil or other contaminants on the bulb, you can clean it off with brake cleaner or other solvent (not rubbing alcohol, which has skin conditioning oils).

Most automotive headlights are halogen lamps which add a halogen gas (typically iodine or bromine) to re-deposit evaporated tungsten back onto the filament.  This allows the lamp to burn much brighter (and hotter) and still have a reasonable lifetime.  By recycling the tungsten back to the filament, halogen gases also minimize the opaque metal film from obscuring the quartz bulb.

#71 Headlight Wiring

November 24, 2012

While replacing a burned out headlight lamp I discovered that the headlight assembly wiring insulation was cracked and stiff and coming apart.  The wires could potentially short circuit against each other or some metal part and blow a fuse so they needed to be repaired.

Apparently this is a common problem on these models (and probably other Volvos).

Repairing is time-consuming but cheaper than replacing the whole harness or entire headlight assembly.  Electrical tape is a short-term solution but may not last long and will make the wires rather stiff.  I was determined to do it right with heat shrink tubing:

Headlight assembly removed.

Glass lens detached.

Reflector pulled out (no fasteners).

One wire covered. Contacts must be released from connectors to permit tubing to be slipped over wires.

All four wires covered and tubing shrunk down with heat to thicken the insulation.

The brown wires are doubled up at the main connector so for these you have to remove the pins from the individual lamp connectors.  Bigger diameter tubing must be used here to slide over the larger contacts.  3/16″ would be ideal but I only had 1/4″ handy and it worked OK, just a little over-sized.  1/8″ for the yellow and white wires was fine.

Reassembled and put lamps back in (new low-beam lamps for item #72) and installed headlights back in car.  Repaired wiring on both sides, L & R.

$2-5, depending on how much shrink tubing you buy.

Technical Notes

Heat shrink tubing is particularly useful for many wiring tasks as an insulator.  You can protect exposed terminals or cover a splice to insulate and water-proof a connection.

Tubing comes in many different sizes and colors and lengths, easily cut to fit.  It also comes in a few shrink ratios with 2:1 being most common.  3:1 and 4:1 are also available but these tend to be thinner.

Heat shrink is tubular so one end must always be free to install it; it cannot be wrapped or slide onto wires like tape or split tubing.

A heat gun (like a super-hot hair dryer) is the usual tool for shrinking the tubing down but a soldering iron, lighter, micro torch or even a match will work if you’re careful.

Shrink tubing is created by taking the basic material and stretching it out 2x (or 3x or 4x, depending on spec) to the tubing diameter.  It is sold in this expanded (nominal) diameter.  Diameter after heating (recovery) will be 1/2 (or 1/3 or 1/4) nominal but will tighten and conform to the size/shape of the object being covered before then if sized properly.

#70 Rear Brakes / Deep Rumbling

November 24, 2012

****Note IMPORTANT safety update near end of posting****


Rear brakes were done separately but could have been done at the same time as front brakes (#69) as one job.  As mentioned in that post, I wanted to verify that the vibration was due to rear brake problems, hence the separate topic.

The deep rumbling sound seems to be well-known with this model as a rear brake issue where the pads are set at a certain angle against the rotor surface.  This condition sets up a strong vibration through the car.  Volvo addresses this with a special shim kit that changes the angle of the pad very slightly or changes the deflection of the pad or something that improves the situation.  From what I have researched, it is more an issue with worn pads and old or resurfaced rotors, so often new pads and rotors solve the problem.  But to make doubly sure, I installed these special shims which didn’t cost much or add any real time.

Started by removing the rear wheels, brake pads and calipers.  Before removing the wheels I wiggled and spun each tire to make sure the rear wheel hub/bearing is not loose or noisy and that it spins freely.

Wheels off, ready for brake work.

Compare old brake pads to new ones. Old ones nearly worn down; very little material left.

Old rotor/disc off and caliper supported by box.

Unlike the front brakes, I am not replacing the rear calipers so supported them on a box where they wouldn’t hang on the fragile brake line.

Pulled rotors off and replaced with new Meyle discs.  The parking brake must be released for this because it works by clamping brake shoes inside the rear rotors.  The rotor is held on with only one small locating pin.  These came off with little effort for me but many people report the need to coax discs loose with a mallet.

Old rotors were not badly worn and didn’t have deep grooves. These might have been successfully resurfaced but new ones were so cheap I replaced them anyway.

Checked parking brake shoe pad thickness and condition as well as the spring, which were acceptable but the pads were worn fairly low; in hindsight I should have ordered new shoes but these don’t wear very quickly (only when you try to drive with them engaged or to stop the car by hand).

Scoured rust and dirt off the wheel hub with a wire brush and liberally washed down the whole wheel assembly and parking brake with brake cleaner spray.  The wheel hub needs to be relatively clean so that the rotor mates flush with it.

Cleaned up wheel hub and parking brake parts.

Washed down both faces of the new rotors with brake cleaner and wiped clean to make sure no oils or dust are present before installing them on the wheel.  I also smeared a little silicone brake lube on the wheel hub where the rotor mates up to ensure easy removal in the future (they tend to rust together).

Shiny new Meyle brake disc with rusty worn old rotor.

Hole sizes on the rotor allow the disc to be eccentric (not concentric) with respect to the wheel hub.  This can cause vibration and on the rear brakes it can cause the parking brake to wear badly.

Slop/play in rotor allows it to be eccentric (not perfectly concentric).

Using the cone-shaped wheel lug bolts to temporarily attach the rotor, they center the disc perfectly to secure with the locating pin.

Result is concentric rotor position to avoid vibration and parking brake wear.

New rotor installed. Beautiful disc won’t look this nice for long…

Inspected calipers for leakage or other damage/wear.  Finding none, I can avoid rebuilding the calipers and just need to clean them up a bit.

Caliper piston boots are in good shape and no sign of brake fluid leakage; rebuilding not needed. Pistons on both sides pushed back into caliper to accommodate new thicker brake pads.

After removing some brake fluid from the reservoir, pushed the pistons (one on each side of the rotor in the rear) back into the calipers to allow for new thicker pads.

Installed calipers back onto the wheel hub with bolts properly torqued.

Calipers cleaned up and reattached to wheel, ready for brake pads.

Installed new ATE pads using silicone brake lube on the backs as recommended.  Used special L-shaped shims which change the pad angle very slightly to avoid the horrible vibration.  Oriented with arrows up and lube on both sides.

Special shim solves noise problems with rear brakes. Piston pushes in center of pad so shim transfers more pressure on the half of the pad with the arrow. Used silicone brake lube on the back of the pads as well as the shim to minimize brake squeal.

Arrows point up on both inside and outside shims. On both L/R sides this is also the direction of wheel rotation going forward.

Pads and shims seated against rotor inside caliper, ready to secure with hardware.

Installed a new sheet metal pad retainer in the calipers along with properly lubricated new slide pins which tap into place.

Retainer secures pads in caliper while lubricated pins clamp the retainer and guide the pads in/out.



 ****IMPORTANT safety update 6/14/14****

The retainer/guide pins that came with the hardware kit from FCP were improperly made.  The compression ferrules (C-shaped rings)  that hold the pin in the caliper body are too large and can’t be driven into the body.  Because of this the pins worked free on three of the four positions and the brake pads were loose and not fully functional.  This is an important safety consideration.  While perhaps not a high risk, the rear brake function was compromised.  Thanks very much to alert reader Ken Gill (who experienced this himself) who warned me about it.

When checking the situation I found that on the right side the upper pin was missing and the lower one was only partly inserted.  The retainer was completely gone.

Lower pin loose; upper pin and retainer missing.

Lower pin loose; upper pin and retainer missing.

The pads were still in place but swimming around and not doing much work, as evidenced by a lot of rust on the disc.

Rusty rotor indicates no braking action.

Rusty rotor indicates no braking action.

Left side was a little better but also had problems.  One pin was very loose while the other was mostly in place, as was the retainer.

Left side upper pin still in place but lower pin was halfway out.

Left side upper pin still in place but lower pin was halfway out.

Left side was better than right but still shows rust which indicates poor braking action.

Left side was better than right but still shows rust which indicates poor braking action.

Basic problem is that the compressible ferrules on the end of the pins are too large to fit in the mating hole in the caliper, even with reasonable hammering.  While these problematic pins were part of a kit from FCP I suspect they are generic commodities and could be supplied with other kits or pad sets.  Re-use of original pins is a good idea if you run into this situation.

Good new pins measure 7.4mm while bad ones are 8.0mm.

Good new pins measure 7.4mm while bad ones are 8.0mm.  8mm is too large to hammer the pins into place to be properly retained.

Was tempted to buy genuine OEM Volvo parts but they are expensive and I would have to go on a weekday to buy them, delaying this repair.  So I bought a cheap ($9) kit from Autozone and it worked very well.

Duralast H5551 from Autozone works well and costs only $9 for both wheels.

Duralast H5551 from Autozone works well and costs only $9 for both wheels.

Put the new retainer and pins (after lubing) in and tapped them all the way in as they are supposed to be secured.

Tapped pin heads all the way.  Need punch to drive them beyond caliper body.

Tapped pin heads all the way. Need punch to drive them beyond caliper body.

Properly secured pins should project well beyond caliper body.

Properly secured pins should project well beyond caliper body.

Now that the rear pads are properly secured I can test drive the car.  To verify that they are now working, I took before and after photos of the worst performer, the right rear rotor.

With loose pins, this rotor was hardly used and rust built up on surface.

With loose pins, this rotor was hardly used and rust built up on surface.

After driving around the neighborhood and braking just a little from moderate speeds, the rotor now shows proper use.

After driving around the neighborhood and braking just a little from moderate speeds, the rotor now shows proper use.

Because the rear brakes do only 20-25% of the work, rear brake problems are not noticeable unless you are looking for trouble.  If you suspect you have this problem, you can check it without lifting the car or pulling the wheels.  Just crawl under the rear with a strong light and visually inspect.  Retainer should be in place under both pins and those pins should be fully engaged in the caliper body.

Rear pins can be inspected from below rear of car without lifting.  This example shows retainer and upper pin in place but lower pin halfway out.

Rear pins can be inspected from below rear of car without lifting. This example shows retainer and upper pin in place but lower pin halfway out.

** End of update; back to original post: **


While brake lube is essential on slide pins and recommended to reduce noise on the backs of the pads, it is vital that no grease gets on the rotor faces or friction pad surfaces.

Re-adjusted parking brake for each wheel per factory specs and checked before putting wheels back on.

Installed new caps over the bleed ports since the original ones were very stiff and disintegrating.

New bleed port caps.

Put wheels back on and drove the car deliberately to condition the brake pads and rotors.  This brake bedding procedure involves multiple brake operations from 60mph to 10mph (no stopping) in rapid succession.

Brakes feel fine and respond firmly with no significant noise or vibration.  After driving quite a bit with the new pads, rotors and shims the horrible vibration problem seems to have gone away.  Will see how long this lasts…hopefully for years.  No such problems with my 850 sedan so it’s promising.

$29 Brake Pads, $72 Rotors, $15 Hardware Kit, $6 Shims, 2x$2 Bleed Caps = $126 Total

Technical Notes

Rear brakes have a similar design as the front but have smaller pads because they do much less of the work to stop the car (~25%).  The brakes are also slightly more complex because the parking brake mechanism is incorporated into the rear rotors.  See previous post #69 for more detailed description of rotor and caliper function.

#69 Front Brakes

November 23, 2012

The vehicle has been making a loud rumbling sound that shakes the whole car when the brakes are applied in normal driving.  Front brake pads have quite a bit of life left but the rotors (American terminology for brake discs) have a fair bit of irregular wear.  It appears that previous brake jobs simply installed new pads without replacing or smoothing the rotors.  Because the vibration in the car occurs only after the brake have been used a bit, I suspect the irregularity in the rotors is amplified by thermal expansion from some brake use.

The rumbling is most likely due to a rear brakes problem (see post #70 for details) but I wanted to rule out problems with the front since the they do roughly 75% of the work on this car.  The front brakes needed a lot of attention anyway.  I tackled front and rear separately to validate the assumption about the source of noise and to spread the work out over a couple days.  Brake work front and rear can be done at different times but should always be done on both L and R at the same time so performance and behavior is equal on both sides.

When I last worked on the caliper slide pins (#61) I also observed that the driver side caliper piston dust boot was torn and needed to be replaced.  The brake pads on the car are also of questionable quality; they look like cheap after-market pads.  As mentioned, the rotors had significant irregular wear.  So I want to make the brakes like new on this project car, and that means new pads, rotors, calipers and hardware.

Since the calipers need attention I considered rebuilding them which involves cleaning and replacement of piston seal and dust boot plus new slide pin and seals.  But that’s a fair bit of work and I can get quality re-manufactured calipers for a lot less than new factory parts so I decided to save some time and use rebuilt calipers.  Went with Beck/Arnley which were very reasonably priced at Advanced Auto Parts with a coupon.

Started by removing the front wheels, calipers, pads and caliper brackets.

Front wheels off, ready for brake work.

Caliper dismounted and supported with both sides brake pads shown.

Outer brake pad removed from caliper bracket. Caliper disconnected from hydraulic line which is capped off to minimize leakage.

Caliper bracket removed along with locating pin securing rotor disc to wheel hub.

Old calipers are being replaced so disconnected them from their brake lines for return to supplier to get the COR (acronym for “cash on return”, often incorrectly termed core) charge refunded.

Pulled rotors off and replaced them with new Meyle discs.  I considered having the old rotors resurfaced but after a lot of research I find very little support for this.  Lots of bad experience out there with resurfacing Volvo brake rotors; if they can be turned at all they are prone to cracking and warping.  See Tech Note below.

LH disc had several deep gouges in rotor surface plus quite a bit of irregular wear.

RH disc had a deep gouge and lots of irregular wear.  Needed to be replaced, not resurfaced.

Shiny new rotor matches old worn one perfectly.

Scrubbed wheel hubs clean and washed down with brake cleaner to ensure parallel contact between hub and rotor.

Clean wheel hub is essential before installing rotor.

Washed down both faces of the new rotors with brake cleaner and wiped clean to make sure no oils or dust are present.  Secured rotor to wheel after applying a bit of silicone lube on the mating surfaces.

Conical feature of wheel lug bolts help center rotor on hub before tightening locating pin.

Rotor has some play when mating to wheel hub.  To ensure concentricity, I temporarily threaded the wheel lug bolts into place.  Their conical shape aligns the rotor perfectly with the hub.  Otherwise, the slop or play can give the disc an eccentric rotation which can cause vibration.  I do not have the equipment to check run-out although that is recommended when doing brakes.

Reinstalled new caliper brackets and used new bolts to secure them to the wheel hubs, torqued to spec.

New caliper bracket secured with new bolts to wheel hub. Locating pin secures rotor to hub at concentric position.

For brake pads I chose to stick with Volvo factory parts.  Volvo is particularly good with the safety of their cars and brake systems are obviously an important element.  Their pads give an optimal combination of performance, wear, noise and dust.  Lots of discussion on Volvo forums where people have trouble with after-market pads but factory pads seem to have the least trouble (although some people think they generate too much dust).  Volvo pads were not terribly expensive so it was an easy decision.

Old pads had a lot of life left but were cheap and falling apart.

Compare old pads (top) to new (bot).

Volvo pads have a bevel cut on the trailing edge (forward direction) and a dust slot down the middle.

Replaced dirty old calipers with remanufactured units.  These turned out to be exact replacements with Volvo and ATE markings.

Old calipers were grimy and at one had a torn piston dust boot. Instead of cleaning and rebuilding, I chose to replace with reman units.

Reman calipers were exact matches because…

…they were rebuilt from OEM Volvo parts.

Connected calipers back up to the hydraulic lines and supported on a box to not strain the brake hose.  Installed pads using high temp silicone grease on the backs as recommended.  Outer pads go onto the bracket and inner pad attaches to caliper with piston hole retainer.

Inner pad installed on caliper and outer pad on bracket.

Installed calipers back onto the rotor and bracket.  Secured by tightening the slide pins (note this requires an unusual 7mm hex bit).  I greased the caliper slide pins once more with brake lube.

New calipers on wheel with pads straddling new rotor. New wire retainer installed which pulls outer caliper down snug.  It will never look this nice again.

Closeup side view of new caliper and pads and rotor, ready for action.

Front end closeup of new brakes.

The liberal use of brake lube is needed for backs of pads and caliper slide pins.  However, it is critical to keep it off the friction surfaces (rotor faces and brake pad faces).  I took great care to keep the braking surfaces clean and dry.

With new calipers the air had to be bled out, much like in post #62.  Did this after pumping the brake pedal to push the pads tight to the rotor.  Just enough fluid replaced to make sure no more air bubbles come out.

Put wheels back on and drove the car deliberately to condition the brake pads and rotors.  This brake bedding procedure involves multiple brake operations from 60mph to 10mph (no stopping) in rapid succession.

Front brakes now feel fine and respond firmly with no significant noise or vibration with fresh, like-new brakes on the front.  Deep rumbling noise and vibration is somewhat improved, which means some of the problem is due to front brakes.   Rear brakes next (#70) to finish it off.

$119 Calipers, $53 Brake Pads, $58 Rotors, $11 Caliper Bolts = $243 Total

Technical Notes

Front disc brakes on the 850 (like many other cars) do most of the work– perhaps 70-80% of the stopping energy.  If you have to choose a priority for brakes, go with front instead of rears.

Disc brakes are very simple and easy to understand.  Basically a metal disc is attached to each wheel and a caliper with friction pads straddles the rotor.  When the brake pedal is pushed, the hydraulic fluid forces a piston in the caliper outwards, which squeezes the rotor between the brake pads.  The mechanical energy of the car in motion is transferred into the heat of friction and the car decelerates or stops as needed.

Disc resurfacing or turning involves chucking the rotors on a lathe and applying a cutting edge to both sides to smooth the disc faces to perfectly flat and parallel surfaces. If the resulting finished thickness is less than factory specifications (due to wear or deep gouges), the rotor must be replaced.  This can be performed on most cars and is commonly done at all brake shops.  However, for Volvos this seems to be an issue; I find very few examples of success with turning rotors and lots of horror stories on multiple forums.

Where to Buy Parts

November 16, 2012

This post is for my buddy Ron who needs to occasionally buy parts for his daughter’s Volvo S40.  It applies to the model 850 like this blog’s project car and any other Volvo parts needs in the USA.

Volvo parts can get very expensive at dealer shops so that is a last resort if you are trying to be economical.  Sometimes you just really need a part and you need it today.  If so and you have a Volvo shop in your area, that is your only choice.

Sometimes your local auto parts shops have stock in something you need.  These are almost always generic or aftermarket parts but for some things that’s OK.  I find Advance Auto Parts useful along with Pep Boys and AutoZone.  O’Reilly Auto Parts has surprised me a few times.  They seem to stock more unusual items for European cars than the other places.  I have lucked out with them on a cam position sensor and a V90/960 ignition coil (a real Volvo part was inside the generic box at a great price!)

For fluids, filters, lamps and really common items like this, don’t forget Walmart.  It’s cheapest by far for commodities.  Local auto parts shops are the next best bet.

In general if you can plan ahead and give yourself time to do repair or maintenance, mail order is the best way to go.  For this I have three favorite sources:

Volvo Parts Webstore is the cheapest way to buy  original equipment manufacturer (OEM) parts (genuine Volvo.)   www.volvopartswebstore.com    Their prices seem to be much better than the local dealers and sometimes they are very reasonable.  They have a nice parts breakdown index for every model which is particularly helpful to know the exact part you need.  Parts are shipped from Chicago.

IPD has a lot of fun and interesting items and the have a colorful and useful web page.  www.ipdusa.com     It’s easy to search for what you want.  Many are aftermarket parts but generally very high quality (some are performance or better than factory parts).  Parts are shipped from Portland, Oregon.

FCP Groton has most of the parts I need but not as much info or details on their website.   www.fcpgroton.com    Many of their parts are aftermarket and some are less than top quality so you need to consider where you want the more expensive OEM part and where cheaper parts are acceptable, and they usually offer two or three grades.  Parts ship from Boston.

For every part you need to check prices with all three sources.  One place may have a significant savings over the others.  Shipping cost should be factored in as well; sometimes IPD and FCP have free shipping which is nice for heavy items, although it won’t be quick delivery.  All will have certain items in stock but often I have to go with one or the other based on what they carry or what is in stock.  Beyond that it comes down to price.  So I use all three regularly to get parts for both of my 850s.

Edit 4/7/2013:  Forgot to mention good sources of used parts which I have tried over the years.  These are particularly useful for less-common parts or where you want a larger expensive assembly for low cost. Side mirrors, seats, headlight/tail light assemblies, interior and exterior trim, visors, ash tray, console, relays, switches and modules and such things can be found for pennies on the dollar vs. new.

First is a local wrecking yard which allows you to remove your own parts.  These are mostly found in larger towns and cities so you may have to travel for this.  Typically they organize their junk lot by manufacturer so you would want to locate all the Volvos first, then hope they have the same or similar model as yours and that the parts are not already removed or damaged.  This approach has no guarantee of finding exactly what you want but may surprise you and the price is great.  It’s a messy job climbing through wrecked cars in a dirty lot but often worth the trouble.  Factory radios are usually the first thing to go so you’re unlikely to find one in a salvage lot.  You will need to bring your own tools appropriate to remove the items needed.

The second source of parts is on eBay.  Seems someone is always selling individual parts from their own wrecked car.  The good thing here is that you may find exactly what you want and you have some idea of its condition.

Obviously with used parts you have no guarantee or warranty but with 850s we are usually just happy to find anything and cheaper is better.

Black Hole of 850

October 23, 2012

A cynical mind might presume the topic is the car itself; after all, the newest model 850 is going on 16 years old and some days it seems there is no end to costly repairs.  In this case, I am actually offering up a potentially helpful tip for my fellow Volvo owners.

Working under the hood a lot we often drop parts, fasteners, tools and such.  If you’re lucky they land on top of something and you can easily retrieve them.  But Murphy says the lost item will end up in a difficult location.  In my experience there is one spot on this car that attracts small objects dropped in the engine compartment.  More than a few times I have found a bolt or drive socket or something in this location, and it is difficult to find unless you know to look here.

This “black hole” is the end of the control arm behind either front wheel hub.  The control arm shape and angle acts like a funnel and tends to direct small objects out to the end tucked under the CV joint.  Next time you lose something under the hood, check here if you can’t find it.

Ends of control arms are a “black hole” on this car. Small objects seem to find their way to this spot and are impossible to find unless you know to look here.

For retrieving objects you can see but can’t reach there are three really useful tools that every 850 DIYer needs to have (besides a strong flashlight/torch):

First is the flexible claw which securely grasps small parts and tools.

Second is the telescoping magnet retriever, useful for steel parts which the claw can’t grasp.

Third is a reaching grabber tool which can save you the trouble of crawling under the car for something on the ground.

#68 Cooling Fan Relay

October 22, 2012

One hot day I noticed that the air conditioning wasn’t very cool while stopped at an intersection and I heard the AC compressor clutch cycling every 4 to 5 seconds.  When the car started moving again the air got cooler so I started thinking what might cause this condition.

The AC compressor will cycle with the temp control thermostat but that wasn’t switching off because it was still hot in the car.  The other things that control the compressor clutch are the high and low refrigerant pressure switches.  I thought about the refrigerant cycle and how the condenser (thinner radiator in front of the engine cooling radiator) exchanges the heat from refrigerant expansion and allows the hot gas to condense back into liquid.  If there is no air flow through the condenser (such as when the car is not moving), this heat exchange will be minimal so the refrigerant stays hot and gaseous at higher pressures.  That will cause the high pressure switch to open and shut off the clutch.

To prevent this condition, the cooling fan behind the radiator switches on with the air conditioning to keep some air flow through the condenser when idling/stopped.  That should keep the refrigerant cycle flowing properly without activating the pressure switches.

The cooling fan has two speeds, one for AC and one for engine cooling.  Engine cooling rarely requires supplemental fan cooling, so the fan doesn’t often come on when the AC is switched off.

The cooling fan is switched on via the cooling fan relay module.  This cooling fan relay is located just under the top shroud above the fan itself and is activated by control signals from the engine control module (ECM).  If the ECM wants to switch on engine cooling, it sends that control signal for high speed; if the AC is switched on, the ECM sends the control signal for the low speed relay.  Module circuitry prevents both from being on at the same time; the cooling speed relay has to be off to enable the AC speed relay.

Wiring diagram shows both relays in the cooling fan relay module.

I observed that the cooling fan was not running when the AC was switched on.  Tried wiggling wires and tapping on the relay module and discovered that the fan would start running if I banged on the relay.  Thinking there was a problem with the relay contacts, I removed the module and opened it up to clean the relay contacts.  Sealed it back up with silicone caulk because I damaged the edge of the cover.  Also sprayed contact cleaner on the connector pins and sockets before plugging them back in.

The fan still would not work until the relay was tapped hard.  I tried wiggling individual wires to see if one of them had a problem with no results.  Determined that something was wrong inside the relay, either a weak coil or poor contacts.

Replaced the cooling fan relay and now it switches on when the AC is working.

$38.89

#67 Recirc Air Damper, Round 2

October 22, 2012

That recirculating air damper previously repaired in #30 stopped working.  You can tell if the damper is moving because the air flow from the vents is more quiet in the fresh air position (default position when the arm breaks) and gives more noise when moving towards recirculating air.  So the tone/sound of air flow is the most obvious indicator of damper operation.  You can also tell by air flow in the inlets under the windshield wipers just under the edge of the hood.  In recirc mode there is no air moving and in normal/fresh mode you can feel/hear air being pulled through those intakes.

Removed the glove box liner and observed that the plastic lever (damper intermediate arm) was not broken this time but had fallen off the motor shaft.  It’s a snug fit with no fasteners so I’m not sure if I did not push it tight previously or it’s working itself off.  After sliding it back into place, I watched the arm move as I switched between fresh and recirc air.  Noticed a slight wobble half-way through the cycle which might be putting a side load on the arm.  This motion might cause the arm to walk itself off the shaft over time, so will keep an eye on this.  May have to add some Loctite or other removable adhesive onto that connection.

Previously replaced damper arm is that black lever in the middle of the photo (above and to left of blower) which connects the damper wire to the motor shaft.

$0

#66 Serpentine Belt

October 20, 2012

The serpentine belt is a very familiar sight in most modern cars; it snakes ;) around one side of the engine connecting various parts together.  Its purpose is to tap into engine power to drive various accessories, most typically the alternator (electrical generator), power steering pump and air conditioning compressor.  On this car the serpentine accessory drive belt is located on the right hand side (US passenger) of the car.  A diagram of the routing is shown below.

The crankshaft pulley is at left on the bottom.  From there the belt winds to the right around the air conditioning compressor, up around the alternator, down and over to an idler pulley, up to the power steering pump and then back to the crankshaft past a belt tensioner which keeps it tight to all the pulleys.

As with all cars this belt needs to be replaced if it is cracking, fraying or otherwise in danger of breaking.  Unlike the timing belt (#65), it is not a catastrophic failure to have this one break, although you lose power steering and the battery stops charging.  Nevertheless, it is highly advised to replace this belt based on mileage, age or condition.  Since I had to remove the serpentine belt to get to the timing belt, this was a convenient time to replace this accessory belt.

After noting the correct belt routing (diagram or photo), the belt is removed simply by rotating the tensioner arm forward with a lever and then slipping the belt off the various pulleys.  IPD makes a very nice and handy belt tool that is perfect for rotating the tensioner (through the square notch in the tensioner) and then has a thick wire pin with a long handle to lock it in the relaxed position so you can use both hands to work the belt on or off.

Serpentine belt tool quickly and easily releases tension to allow belt removal/installation.

Tensioner locked into place.

Removing old serpentine belt.

Old belt (top) was in fair condition but the ribs were starting to crack.  Since I had to remove this belt to replace the timing belt behind it, this was a perfect time to replace it with a new belt (bottom).

New serpentine belt installed.

$ 21.77

#65 Timing Belt

October 20, 2012

This is a big and important topic so bear with me on this long entry…

Replacing the timing belt and related parts is an important preventive maintenance (PM) task every 70K miles.  Volvo 850s have interference engines where valves and pistons share the same space.  If the belt breaks and timing is lost, valves and pistons may collide and be damaged.  On this old car such damage is practically catastrophic; it would be too expensive to justify a repair unless you have lots of time and experience and special tools to rebuild the engine internals, so this is a very important task.

This car is overdue for its second belt change at 150K.  Assuming original rollers, I decided to replace the belt, rollers and tensioner but skip the water pump.  There are no leaks and the water pump spins freely, smoothly and noiselessly and is likely to start leaking long before it binds up.  There are strong opinions on both sides of the question of replace or not on water pumps with the timing belt; after checking pump condition I decided against replacing it.

Bought a complete timing belt kit from FCP with factory parts (supposedly).  Glad I replaced the rollers along with the belt since they both had issues.

I won’t give a step-by-step procedure here, just some highlights.  There are good detailed procedures on other forums.  I like Ozark Lee’s writeup which is located at http://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=19831

Moving the coolant reservoir out of the way really improves access.

Access to the idler roller is easier if the serpentine belt tensioner is removed.

30mm socket on long ratchet used to rotate (CW only!) crankshaft and camshafts to line up timing marks. Removing spark plugs helps reduce force required but can be done with them in. Interior flap clamped out of way.

Highlighted camshaft sprocket timing marks so they are more easily seen to line up to reference notches in rear cover.

Crankshaft timing marks that many people have difficulty locating. Upper one is fixed on the engine block. Lower one on the pulley rotates with the crankshaft. When these are lined up the cam sprockets should align with their marks.  There may be a notch in the crankshaft sprocket valley at the same location instead of the raised spot on the pulley.

Old belt ready to remove.

This blue locking fixture from IPD is simple insurance against either camshaft moving while working in the area and routing new belt.  Need to get at least three pins engaged to really lock.

This is the pinch point under the crank pulley where it’s difficult to pull the belt through. It can be wrestled out with a lot of time and fussing but since the belt is getting replaced…

…it is easier just to cut the belt and pull the ends out.

Old and replacement idler rollers. The old wheel spun roughly with difficulty and seems to be on its way to freezing up. Replacement was essential.

Removing the tensioner roller is difficult because it’s hard to get a T45 bit in between the bolt and the wheel well. A standard Torx bit drive with a thin, long 3/8″ ratchet will fit and wedging a tool in the gap keeps it secure in the bolt socket.

This tool combination works to get the tensioner roller unfastened. The long ratchet gives lots of leverage and the thin profile fits in the narrow clearance.

This unibody drive on left allows a few mm more clearance than the traditional Torx 3/8 socket drive.

Old and new tensioner rollers. Old wheel spun noisily which indicates that the bearings are failing. Needed replacement.

Old and replacement hydraulic cylinders. Nothing obviously wrong with the old part but it’s advisable to replace it to ensure critical belt tension.

Water pump shows no signs of leaks and spins freely, smoothly and without noise, so I left it alone. If it was leaking, moved roughly or made noise, I would have replaced it.

New timing belt roughly positioned, ready for tensioner and final belt placement.

For me final belt positioning is the hardest part of this task.  I have done it four or five times now and I still don’t have a foolproof method.  Things seem different every time so it’s trial and error for me.  I have read many different guides and none quite seem to work precisely.

Mark some sort of label with mileage so that future owners and service shops know when the timing belt was changed.

All the parts changed on this job along with their replacements.

My brief walk-through of the process:

  1. Set parking brake and block rear wheels.
  2. Break loose the RH front wheel lug nuts.
  3. Raise front of car and secure on jack stands.
  4. Remove serpentine belt and its tensioner.
  5. Remove spark plug cover and fuel line clamp on timing belt rear cover.
  6. Remove timing belt front cover.
  7. Unplug sensor connector on coolant reservoir and move on top of engine.
  8. Remove front right wheel.
  9. Move splash guard flap in wheel well and clamp in open position to access crankshaft pulley.
  10. Remove guard under crankshaft pulley.
  11. Crank engine around in CW direction using 30mm socket until the camshaft sprocket marks line up with their notches in the rear cover.
  12. Verify timing mark on crankshaft pulley lines up with the mark on the engine block.  (Don’t trust existing belt position; it could be off one or two notches.)
  13. Install camshaft sprocket locking tool or secure the sprockets with cable ties, if desired for extra security.
  14. Remove timing belt rear cover.
  15. Remove timing belt tensioner, starting with the upper bolt.
  16. Remove old timing belt.  Fight it off at bottom of crankshaft pulley (hard and time-consuming) or just cut it (quick and easy).
  17. Remove idler roller.
  18. Remove tensioner roller.  This is a tough one without a short T45 tool and long ratchet.
  19. Install new tensioner roller.  No chance to tighten to spec since it is impossible to get a torque wrench in there.  Specified 18 ft-lb is not terribly tight, so an easy torque by hand.
  20. Install new idler roller.
  21. Install new timing belt starting at that pinch point under the crankshaft pulley.  It’s a bit of fussing and twisting but it’s much easier to install the belt than to remove one.  Rough in place loosely in proper routing path.
  22. Install new tensioner cylinder but do not pull locking pin yet.
  23. Make final routing of timing belt around tensioner roller.  Ensure it is tight (no slack), starting at lower right from crank pulley, maintaining tension as you go.
  24. Reinstall rear timing cover and secure in place.
  25. Verify timing marks one last time on crankshaft pulley and camshaft sprockets.
  26. Remove any camshaft locking devices.
  27. Rotate engine twice at crankshaft until camshaft sprockets complete one revolution back to their timing marks.  Verify that the belt did not slip any teeth (marks at camshaft and crankshaft line up at same time).  This is where it may slip a tooth if something was not quite right.
  28. Once you are confident of the timing and installation, pull the locking pin to release the tensioner cylinder pin.  It will now push the tensioner roller firmly against the belt.
  29. Rotate the engine through one more camshaft sprocket revolution and check timing marks one last time at both locations.
  30. Install white plastic spacer between tensioner end and tensioner roller pad.  Re-use old spacer if new one is not provided with new hydraulic cylinder.
  31. Start engine and observe that it runs well and the timing belt moves smoothly.
  32. Stop engine and button things up (replace guard, covers, flap, etc.)
  33. Install wheel and lower car.  Tighten lug nuts to proper torque (81 ft-lb).  Remove wheel chocks.
  34. Reinstall serpentine belt tensioner and serpentine belt.  This is the perfect time to replace the belt if needed or based on age.
  35. Move coolant reservoir back into place with sensor connector plugged back in.
  36. At this point everything should be back in place and secure.
  37. Start engine and verify smooth movement of serpentine belt.
  38. Record mileage on a label to indicate when the timing belt was changed.
  39. Drive the car a short distance through varying RPMs to make sure there are no surprises before you really need the car.
  40. Drink a beer or two to celebrate a job well done and hundreds of dollars saved.

This procedure took about four hours of deliberate, careful work; this is not a job to be rushed because if you miss something important it could be a big problem or cause you to do hours of re-work.  Newbies will take longer; this was my fourth time so I had some experience and all the right tools.  I was also taking photos along the way.

$214.95 Timing Belt Kit

Technical Notes

The timing belt in this vehicle (and most other modern cars) is a flexible toothed belt which links the engine crankshaft (where the pistons are driven up and down in each cylinder) to the overhead camshafts (which open and close the intake and exhaust valves for each cylinder).  Its purpose is to synchronize the movement of the intake and exhaust valves with the piston cycle in each cylinder so that fuel and air are introduced at the right time for combustion and then waste gases are pushed out at the proper time.  The belt is outside the engine on the RH side under a cover.  If the cover is removed you would see the belt as shown in the diagram below:

The lower gear is on the crankshaft; the upper right sprocket (front of car) is the intake camshaft; the upper left sprocket (rear of car) is the exhaust camshaft.  An idler roller guides the belt on the right and a tensioner roller is above and just to the left of the crankshaft sprocket.  A hydraulic cylinder pushes against the tensioner roller to keep the belt tight.  The large object to the left of the tensioner is the water pump for engine cooling.

This timing belt should be changed every 70K miles or so because if it breaks, the pistons will collide with open valves and wreck the valves and/or the pistons.  The rollers and tensioner should also be replaced at least every other timing belt change because they tend to wear out and can seize up.  Even if the belt is fine, a frozen roller can shred a good belt pretty quickly.  A weak, leaky tensioner can allow the belt to slip teeth on one or more sprockets, which causes the engine to run badly or not at all.  Many people recommend changing the water pump when the rollers and tensioner are replaced because they could also seize up and wreck the belt.

State Inspection / New Rear Tires

October 20, 2012

This is not really a maintenance or repair item worthy of a task number but it is a normal expense for any car owner.

The annual state of Texas vehicle safety inspection was due so I took the car into an authorized shop.  The car passed except for tread on one rear tire where he found one tread wear indicator too close.

Ran to Firestone and got two new tires on the rear.  I like Firestone because you can get a lifetime road hazard warranty which pays for itself with one flat tire.  Plus they have shops all over the country so almost anywhere you go, we can get free tire repair/replacement.

Took it back to the state inspection place and all they had to do was look at the new tires and give us a certificate and new windshield sticker.  Good for another year on this beast!

$214.52 tires, $28.75 inspection

Summer/Fall Pause

October 7, 2012

The car has been largely gone to college with the girls since July so apart from the camshaft position sensor problem (previous entry, #64) I haven’t had much time with it.

The car will be back soon for fall break and I have parts in hand for timing belt and serpentine belt replacement.  May also get to a couple minor things this time around.

Other tasks on the horizon (Thanksgiving or Christmas break?) are brakes, control arms and tie rod ends.  Hoping that solves the mystery clunk up front without involving the struts, which were done before we bought the car.  Will also be looking to see if cabin vibration is due to failed engine mount(s).

#64 Cam Position Sensor

October 2, 2012

The car was running fine but suddenly would not start.  The engine would crank strongly so the starter was working but the engine would not catch and run.

Packed up all the tools and equipment as was practical and drove up to the girls’ college to see what was wrong.  Removed timing belt cover to make sure the belt had not broken and checked for fuel and spark (assuming no problems with air).  No spark so immediately suspected the camshaft position sensor.  This is a fairly common failure which can explain rough engine operation (intermittent failure) or a no-start condition (complete failure).  Volvo refers to the camshaft position sensor as CMP.

The exhaust valve cam shaft rotates once for every two crank shaft revolutions so the engine control computer needs to know which half cycle the cams are in to determine when to fire the spark plugs.  If there is no feedback from the CMP, there will be no spark.  There are no error codes associated with this sensor so the car won’t tell you anything is wrong.  Sometimes a CMP fails electrically with a short circuit or low impedance from the sensor output wire to ground or +12V but in this case no strange readings on my multimeter.  I decided to change the sensor out anyway since it could still be bad, just not obviously so.

Cam position sensor located just aft of the distributor.

CMP cable connector down under distributor; tricky to pull out and disconnect but nothing special or surprising.

Replacing the CMP is fairly easy, just unplug the electrical connector and remove two screws holding it in place.  The CMP is located just aft of the distributor on the LH side near the top of the engine.

New (L) and old (R) sensors shown side-by-side.

Cam sensor rotor which triggers the sensor at the proper half-rotation.

New CMP installed in proper orientation and connected to wiring harness.

Make sure to orient the sensor correctly since it can be installed upside down and this would give exactly the opposite cam position reading.  After securing to the engine, plug the CMP back in and hopefully the car will start.  It may take some cranking because with no spark previously the cylinders get flooded with fuel and you need to work that out with the throttle wide open (pedal to the metal).  Don’t be surprised if it takes a minute of cranking before it starts to catch, which could require a jump start from another car battery.  Once it does catch the engine may run rough until the fuel/air mix settles out.  This is what happened to us and now she runs fine.

I observed a fair bit of corrosion on the connector contacts so suspect it may not have been a sensor failure but maybe a connection failure.  Sometimes just unplugging and re-plugging a corroded connection restores function.  Using a chemical contact cleaner is even better.

$170  A bit pricy for a simple sensor but the engine won’t run without it.

Technical notes

Without fancy equipment there are two simple ways to check for fuel and spark.  On Volvo 850s fuel problems are fairly common; usually the fuel pump itself or the fuel pump relay stop working.  To verify fuel pressure (at least in a general manner), there is a Schrader valve (much like a tire air valve) on the end of the fuel rail on top of the engine towards the front.  Push a small tool into the stem under the cap and see if fuel squirts out; if so, the fuel pump and relay must be working; if not, you need to look for a fuel pump problem.

To check spark, it is easy to pull the spark wire from the center terminal of the distributor and set it near a grounded metal object (such as the strut stud shown below).  If the ignition is working, you will see a spark jump across the gap.

#63 Rear Brake Light Cover, Round 2

July 3, 2012

Replaced the rear brake light cover way back in #22 but was not happy with the color match.  I darkened it up with some trim dye and now it matches very well; close enough for me, anyway.

Before:

After:

#62 Brake Fluid Replacement/Bleed

July 3, 2012

The brake fluid in this car is of unknown quality.  I don’t have those test strips they use in most automotive repair shops to check brake fluid condition.  Color is a general indicator; fresh fluid is nearly clear and it darkens with contamination and reaction with metal lines and brake cylinders.  It was moderately dark in this car, probably not far gone but on its way.

Brake fluid is naturally hygroscopic (absorbs moisture) and over time water from the air gets in where it will slowly corrode the innards of the brake system.  Moisture is also bad because it will boil when heated above 100°C, which reduces braking power.  Brakes can get much hotter than that, so moisture in the line is a real concern.

Safest thing to do is to replace the fluid and flush the lines with fresh material.  Since I had replaced the front brake hoses in #60, I needed to bleed the air out anyway.

Used this great one-man pressure system by Motive Products:

It attaches to the brake fluid reservoir and pressurizes it as if a helper was pushing the brake pedal.  A hand pump allows the user to pressurize the container which can hold a couple quarts of fresh brake fluid so you don’t have to worry about the level in the reservoir.

I bled each brake caliper in proper sequence but drained a lot from each one to get all the old fluid out of the lines and reservoir so that all-new brake fluid was left.  Used synthetic DOT 4 fluid.  Change in color showed when new fluid was coming out (new is clear).

With the Motive bottle pressurizing the master cylinder, bleeding is accomplished simply by attaching a drain hose to each bleed port and then cracking the bleed fitting open.  Made sure that the level in the reservoir never went below MIN and kept the power bleeder pressurized between 10 and 15 psi.

Bleeding can be done with all four wheels on the ground.  The rear fittings are accessible crawling under the car.  The front wheels are more difficult to reach but can be done this way.  However it is much easier to bleed with the wheels off.

When finished I am satisfied that there is no air in the lines and that the braking system has all fresh fluid.  Of course I drove the car around after this to make sure the brakes were in good working condition.

$54 Motive Pressure Bleeder, 4x $3.87 Fluid

#61 Front Brake Caliper Slide Pins/Boots

July 3, 2012

While working on the wheels I observed that the brake caliper slide pin boots on the passenger (RH) side were torn up and the driver (LH) side was fairly crusty as well.

Slide pins guide the two sides of the brake calipers, straddling the brake rotor.  Smooth movement depends on clean and lubricated pins.  Torn boots allow dirt and contaminants in to gum up the works and let the grease dry out or wash away.  The slide pins on both sides moved roughly and with some difficulty, so they needed to be replaced.

While I was replacing the brake hoses (#60) it was a good time to replace the slide pins and boots.

The pins are unscrewed with a rare/unusual 7mm hex drive to allow the caliper to pull up off the rotor.  The old boots are easily pushed out with a screwdriver blade.

Installing the new boots is a major pain.  There is probably some trick to it but I found that with some white grease I could get one end started in the hole and then use a 16mm deep well socket to push it into place.

Greased the new slide pins and inside the new boots.

Used high tech brake lube with microscopic ceramic balls for improved lubrication at the high temperatures experienced in braking.

Put the calipers back on both sides and secured with new slide pins.  The after-market replacement boots have a tapered end to seal against the pin, so a plug on the end is not required.

No apparent results from all this; nothing was really wrong so nothing was improved.  But it likely prevented some problem with the brake calipers binding or something like that.

2x $21.95 for pin/boot kit, $3.17 for brake lube

#60 Front Brake Hoses

July 3, 2012

While replacing the drive axles I observed that the front brake hoses (at least on the driver side) were cracked and brittle.

This is a serious safety concern because if they leak enough the brakes can fail.  Front brakes do most of the work on this model, like most cars.

Some confusion at first on how to remove the old hoses at the female end.  Turns out the male end goes into the brake caliper first (or removed last), then the male nut from the hard line is unscrewed from the female hose end through the supporting bracket.

Male nut on left from hard line is unscrewed from female end of hose through bracket.

Ordered after-market replacements with stainless steel braid sheathing to minimize the chance of bursting and for better protection.

New and improved hose shown above original one.

Installed the replacements on both front brakes.  Requires brake bleeding to get the air out, accomplished in #62.

This is one safety concern scratched off the list.

2x $21.95

 

#59 Coolant Flush and Fill

July 3, 2012

The coolant on this vehicle was a suspicious rusty brown color and of unknown age and composition so I drained it, flushed with a chemical cleaner and refilled with known high-quality coolant.  This has to be done with a cool engine, of course, to avoid getting burned or sprayed with hot fluid.

Brown color could be from mixing different brands of antifreeze or could be caused by corrosion inside the cooling system.  Volvo 850s have an aluminum engine block and aluminum radiator so there is not much iron in the system to rust.  At any rate, the color and some mineralization evident from the thermostat replacement plus the uncertain age and quality of the coolant demand a good flush and fill.

The 850 radiator has no pressure cap to directly access the radiator; everything is done through the plastic coolant expansion tank:

Start by raising the front of the car and supporting securely on jack stands.  Remove the splash guard under the radiator:

Place a catch pan under the radiator drain cock on the driver side (LH) and open the drain port:

Removing the coolant reservoir cap allows air to get in to drain smoothly.  This car had an after-market radiator installed at some point, evident by the drain plug being different in size and type from a real Volvo part.  It also looks newer than the rest of the car.  I measured around 5 quarts from the radiator.

After draining the radiator, replace the drain plug and crack open the engine block drain plug accessed from underneath behind the engine towards the passenger (RH) side:

Coolant from the engine drain splashes all over the place so you need a large pan to capture it all.  Better yet, stick a hose over the port to direct the coolant into a catch pan, which I didn’t do out of laziness.  Didn’t get much coolant out of the engine block but it was good to drain out what was there.

Did this job along with the thermostat replacement (#58).  At this point the thermostat was removed and the housing re-attached so flushing could occur with no thermostat in the way.

After tightening the engine drain plug, I added some Prestone super flush chemical to the reservoir, then filled with distilled water.

As mentioned in the previous thermostat topic, it is important to use only high-quality low-mineral content water in the cooling system.  Mineral buildup causes chemical reactions and gums up the innards.

Closed up the reservoir and ran the engine for 10-15 minutes to get it all circulating through the radiator, engine block and heater core (put cabin temp controls on heat).  That should effectively break up any gunk and rust and minerals in the cooling loop.

Waited for the car to cool down, then drained as before.  After that, I refilled with distilled water only and ran the engine again to get one more good flush with no chemicals.   Drained once more after cool-down.  This is where I installed the new thermostat.

Now the car is ready for fresh coolant.  Something so simple can be so controversial.  Lots of discussion about best or proper coolant for Volvo 850s.  Many people insist only real Volvo coolant should be used, or at least a particular alternative.  Others say just use whatever.  Strong opinions all around and much of it contradictory.  I weighed opinions from reputable forum comments and decided to go with extended life coolant from a major supplier, Prestone for this job.

Mixed half coolant and half distilled water and filled the reservoir for the proper 50/50 ratio.  Ran the engine until it got warm and then topped off the reservoir to keep it level.  Also added more after it cooled off completely.

Of course after draining I re-attached the splash guard.  Also disposed of used coolant properly, not into the sewer.

Cooling system should now be good for a few years at least, with a new thermostat and fresh, high-quality coolant after flushing.

$4 Flush, $13 Coolant, $4 Distilled Water

Technical Notes

Coolant in the car is normally a mixture of coolant solution and water.  Water is the primary ingredient and in some warm climates is all that some people run in their cars.  Coolant keeps the water from freezing in cold climates, which is why many people call it anti-freeze.  By an interesting property of chemistry it also raises the boiling point of the water (so does the pressurized cooling system), so coolant helps in both cold and hot weather.  To call it just anti-freeze is not accurate; it is also coolant and the product you buy says both on the bottle.

Coolant also lubricates the water pump so if the fluid goes bad it can cause problems for the pump.

Extended life coolant adds corrosion-resistant chemicals which allow it to last up to five years, although many people change it more often than that.

#58 Thermostat

July 2, 2012

Most every car has a thermostat and this model is no exception.  The thermostat is a type of valve in line with the engine cooling system which closes to block cooling flow until the engine is warm, then opens when the engine needs cooling.

Thermostats can fail where they are always open.  This condition causes the engine to take a long time to warm up to operating temperatures and provide passenger heating, a problem mainly in cold climates.  The worst scenario is when the thermostat fails closed.  This chokes recirculating coolant flow between the engine and radiator and causes a running engine to quickly overheat.  This is a bad news shut-you-down type of problem that can leave the car on the side of the road.  Don’t want this to happen again (it happened once to us on a family minivan) so I replaced the thermostat in this project car.

After draining the coolant from the radiator, the thermostat is easily accessed on top of the engine.  Two large Torx screws hold it in place but these are usually buggers to break loose if they have been on awhile.  You also need a long T40 drive bit to get around the fuel line.  Many people disconnect and move the fuel tube out of the way but I was able to work around it with the long bit.  Also sprayed penetrating oil (PB Blaster) on the screws the night before and then again before trying to break these screws free.

Old thermostat was not in too bad of shape but it did have some mineral buildup and the gasket was starting to crack.

By the date code (Oct. 2005) it was six or seven years old. Not original to the car but getting long in the tooth.  Also scraped buildup away and cleaned the housing surfaces before installing a new thermostat.

The minerals on the thermostat and around the housing suggest hard water was added to the coolant in the past.  Only distilled or DI water should be used to minimize mineral buildup which can clog internal passages or gum up the thermostat or water pump.

Used a genuine Volvo thermostat to replace the old one.  Should give years of reliable service.

$18.19

#57 Evap Leak / Fuel Tank

July 2, 2012

Like most modern cars, this one has emissions controls to prevent gasoline vapors from leaking to the atmosphere.  Gas vapors from the sealed fuel tank are stored in a charcoal canister near the front of the car where a valve opens to release them into the engine intake manifold at a prescribed time (typically when the engine is warm and revving above idle) to combust.

This evaporative emissions system has a lot of potential for leaking so it is monitored by the engine controller which looks at pressure in the fuel tank at certain times.  If pressure is too low, a check engine light will come on with a corresponding error code (large or small leak).

Intermittently we get a check engine light with P0455:

On Board Diagnostic (OBD-II) code reader shows this to be a large leak:

Some owners might live with this as a nuisance problem but it is likely to get worse and the car cannot pass state inspection with such a problem.  Resetting the fault also resets all engine monitoring systems, which require certain drive cycles to be happy.  The car cannot pass Texas inspection unless the monitors are OK, so this is a potential show stopper.

Two common leaks on this model involve two different hoses which can deteriorate or split with age, heat and vibration.  The easy one is up front, between the radiator and engine.  This connects the evap purge valve to the intake manifold.  This hose was in bad shape and starting to come apart:

Replaced with new hose but I doubt this is the real problem causing the error code since it was probably not leaking bad enough to trigger a large leak code.

Most likely the problem is a short hose on top of the fuel tank.  I experienced this on my other Volvo 850 and it has the same symptoms.  Besides the error code, there is a strong fuel odor in the rear after filling the tank, even outdoors after driving a while.  This is a much bigger fix because the fuel tank has to be dropped to access the hose.

First remove the cover from over the fuel pump from inside the car.  On wagons this is under the rear deck:

Next drain the fuel tank to lighten it for removal.  This can be done by siphoning  but since I had to get to the pump, it is easier to use the pump itself to push gas out through a length of 1/4″ ID tubing:

First you depressurize the line by running the engine with the fuel pump relay (103) pulled.  Then pull the yellow striped hose fitting up and off.  This plastic spark plug boot puller works great for pulling the fuel fitting off the pump:

Then connect the tubing and then hard-wire the fuel pump to run by bridging these two terminals of the relay with some needle nose pliers or something:

Ignition needs to be switched on with a key to run the pump.  Jump the pump until it starts to go dry (foam coming out).

Once the tank is empty, the four cables on top of fuel tank (fuel pump, pressure sensor, level sensor and something else) must be disconnected:

Raise and support the rear of the car, then unclip the retaining ring at the fuel door to free the filler neck:

And push it through the fender to allow it to drop:

Support the tank in the center with a floor jack and remove three bolts securing the tank straps to the chassis.  Lower the tank to the ground where it can be worked on:

The tank can be completely removed by disconnecting four hoses from the underside of the chassis but in this case it is easy enough to work on it in place below the car.

The suspected hose is this one running across the top of the tank with a blue elbow into the tank on left coming from the fuel filler overflow tube on right:

After removing this hose and examining it, a crack is obvious.  This is what I expected and is likely causing the error code when filling up:

Replaced with a new factory hose.  Because this has two different sizes at the ends, it’s hard to make ordinary fuel hose fit, so I ordered the factory part.  Replacement hose is much longer so needs to be cut to match:

New hose installed and hopefully that was the only leak under there:

Raised the tank back up and bolted it snug.  Even empty that takes some fussing and wiggling around.  Had to feed the wires up through the hole as the tank was raised near the rear deck and also had to guide the filler pipe up into place behind the right rear fender.  Secured the filler gasket into the cutout in the fender and re-installed the retaining ring.

After putting a couple of gallons of fuel in the tank I ran the engine to check for fuel leaks before buttoning up the fuel pump cover and all the panels inside the car.

No more fuel smell and no more error codes we hope; time will tell.

This is a very expensive dealer repair ($400+) so once again, DIY is the only way to go.

$11.14 purge hose; $14.78 tank hose

Update 4/24/14I strongly suspect that lowering the tank (which can’t be avoided with this repair) also causes the rear-most evap hose to crack at the roll-0ver valve.  See post #92 for details.  Don’t be surprised to have to change at least that hose as well when this one is repaired; it gives the same result (P0455 error code).

Shiny Red Mechanic’s Stool

July 1, 2012

A great Father’s Day gift from the girls to help me work on their car:  a shiny red mechanic’s stool.

It will be nice to use when not standing or lying down.  This even has a height-adjustable gas spring.

#56 Ash Tray

July 1, 2012

Ash trays on these cars are different than many others.  Here you push to open and push to close.  Unfortunately this spiffy design is a bit weak and the mechanism wears out over time.

Such was the case here.  The ash tray mechanism is worn out or broken so it’s hard to open and close it.

Replaced with a working ash tray in good condition pulled from a wrecked car at a scrapyard.  Cleaned it up first.  Two screws holding it in place.

Not that the girls will need it for cigarette butts, but it’s nice to have one to store little things in.

$10

#55 Ignition Switch

July 1, 2012

Intermittently we have strange symptoms with the car where various things don’t work.  Some or all of these problems occur:

  • Can’t shift out of Park
  • Speedometer doesn’t work
  • Headlights inoperable
  • Tail lights inoperable
  • Turn signals inoperable
  • ABS warning light comes on

While most of these are serious and urgent, the good news is they can all be tied to the ignition switch so we don’t need to troubleshoot each one.  I discovered by wiggling the key in the ignition, these problems go away.

Like most cars, the ignition switch completes multiple independent circuits in its various positions.  The key simply provides a secure means of operating the switch.  It is an electromechanical device which moves electrical contacts between positions.  These contacts wear and degrade over time with use and with exposure to atmospheric contaminants (dust or corrosive chemicals and/or humidity) which can seep into the switch.  Since the contacts are independent and this is an intermittent problem any combination of these symptoms may occur.

It mostly works but sometimes one or more symptoms occur and can be remedied by wiggling the key.  As expected, the problem seems to be getting worse over time so I want to nip this one in the bud before it fails altogether and leaves one of the girls stranded with an inoperable vehicle.

Fortunately the ignition switch is fairly easy to replace and relatively inexpensive.  The lock/actuator is separate so no new keys are needed.

Simply remove the upper and lower covers from the steering column after removing screws underneath.  This gives access to the switch:

It helps to pull the wheel out and down for best access.

Unplug the connector after prying out from the switch with a non-conductive tool :

Unscrew the switch from the steering column and remove it:

Installing the new switch and buttoning up again is simply the reverse of all this.  The switch is keyed to the lock mechanism and the connector to the switch so no mistakes can be made.

The new replacement switch has a clear hole to the inside.  If the old original switch had a hole, I would have tried spraying electrical contact cleaner inside and moving the key through its positions to clean the contacts:

If this had worked, the switch could continue to be used.  Unfortunately the old switch had no openings so I had to replace it.

$49.15

Upon removing the upper and lower steering column covers, I found that they were badly broken; looks like they had been removed before and beaten up a bit.  The original screws holding the lower cover on could no longer be used because they no longer had any plastic to grab on to:

So I got longer M5 screws with decorative washers and attached from the underside:

Instead of being recessed they are now out on the surface, so I blackened them with a permanent marker.  Not ideal but OK and these are not very visible below the steering column anyway.

Pause…Flurry of Activity…Pause

July 1, 2012

The car has been gone for a couple of weeks so nothing has been done since the last post.  But the car is back this week and I am on shutdown for work so will make the most of it with eight tasks planned.  Then another long pause while we’re on vacation and then me working out of town for a while.

It will be several weeks and perhaps longer before I get to work on it again, with the car being gone or me traveling.  Playing this by ear…

#54 Fuel Pump Relay PM

June 17, 2012

Like many modern cars, this one has a fuel pump in the gas tank that pushes fuel up to the engine.  The pump is driven by an electric motor which is switched on by a relay.

The car depends on the pump and relay to provide a steady supply of fuel to the engine to run properly.  It the pump does not operate the engine can’t work.  If the pump operates intermittently the engine will hesitate or stall.

The pump depends on the relay to operate, so a bad relay has the same consequence as a bad pump and it’s hard to tell which is at fault.  Sometimes fuel problems are due to a faulty pump but on Volvo 850s pump relay failures are common.  On this car the fuel pump relay module contains more than just a simple electro-mechanical relay; it also has quite a bit of electronics for relay control.  This circuitry includes a couple of aluminum electrolytic capacitors.

Electrolytic capacitors have operational lifetimes, typically in the thousands of hours.  When they fail they usually cause erratic behavior or disable the circuit altogether.  In this case they can cause the fuel pump relay to switch erratically or not switch at all.

The electrolytic capacitors in the fuel pump relay module can fail at 10-15 years of age, depending on ambient temperatures and how much and how hard the car is driven.

In the case of our project car we have no fuel supply problems but I anticipate trouble soon based on age of the car and mileage.  So to be proactive and avoid future problems, I replaced the capacitors in the fuel pump relay module as a preventive maintenance (PM) task.

The fuel pump relay is located under the hood in the main electrical/fuse box in front of the driver (LH).  Access to the relay is under the cover.

Fuel pump relay module is the red one marked 103.  Remove by simply pulling it out.

Slide the cover off after prying out the retaining latches on both sides.  The relay and electronic circuit are on a printed circuit board (PCB) inside.

The two bigger cylinders are aluminum electrolytic capacitors.  The yellow oval-shaped part nearby is a tantalum (solid electrolytic) capacitor which is more stable and rarely fails.

Screwdriver blade pointing at capacitors.

Removed and replaced the two aluminum electrolytics.  This requires some soldering skills and equipment but is not overly difficult.  I chose replacement parts that had high temp ratings and high quality construction.  The diameter of these caps is larger than the original ones but they still fit.  Polarity is critical so I made sure to maintain + and – terminal orientation.

New caps installed.

Checked the old capacitors for capacitance value as well as equivalent series resistance (ESR).  The big one (100 uF) measured very low value (32uF) with a high ESR (12 ohms).

100uF cap measured only 32uF

100uF cap ESR measured 12 ohms; should be less than 1/4 ohm.

The smaller one (22uF) measured nearly OK but its ESR was also high (4 ohms).  This indicates both capacitors are going bad and would have caused the fuel pump relay module to fail soon.

While I had the soldering iron out I touched up (re-flowed) the solder joints for the relay contacts on the PCB.

Screwdriver tip pointing to one of the relay solder joints. The relay leads were starting to separate, probably due to 15 years of vibration.

Smooth, clean joints after re-flowing solder of relay terminals.

This PM task should buy another 10-15 years with the fuel pump relay; it should out-last the car’s remaining lifetime.  I observed that the relay contacts were quite clean with no wear or pitting indicating contact problems.  I might have cleaned them up if they were in bad shape.

Relay contacts were in excellent condition.

Reassembled and plugged back in the car and ran the engine for 5 min. to make sure it worked.

In this car there are other relays and modules which also have electrolytic caps, so I will have to look into these as well.

This is one case where an old used relay (such as from a scrap car) may not be a suitable replacement part; it is likely to have the same problem with aging electrolytic caps.  Buy new replacements or repair it yourself.

$0.68 for two capacitors

Technical Notes

Relays are basic electro-mechanical devices which use a small control signal to switch a heavier current or different voltage or multiple sets of contacts.  In cars they are used to activate motors (starter, pumps, fans,wipers) or other devices (headlights, windows, heating strips, etc.)

Capacitors  are electronic components which give physical manifestation of the fundamental electrical property of capacitance.  They are used for timing, charge storage, and filtering, among other things.  Electrolytic capacitors use a solid (more expensive) or liquid (cheap and common) electrolyte material to enable relatively large capacitance in a small area.  Aluminum electrolytic capacitors, such as used  in the fuel pump relay, have a limited life.  The liquid electrolyte degrades with temperature (hot and cold), applied voltage vs. rated voltage, current flow, and just plain time (they even have a non-operating shelf life). Quality electrolyte solution is also a factor; better electrolytes cost more but cheap ones are often used to save money.

When the electrolyte degrades it decreases capacitance and increases internal resistance; both bad for most circuits.  The circuits they are part of start to behave badly and may fail completely.

Sometimes electrolytics can be diagnosed visually because they bulge or leak their chemical contents.  However, as in this case, the caps were bad but looked fine.  It requires instruments to properly check old caps that pass visual inspection.  Besides, 15-year old caps should be replaced just based on age.

Electrolytic caps with higher temperature ratings last longer.  A higher voltage capacitor can always be used in any circuit and that makes it last longer as well, but they tend to grow in size with voltage, so space may limit the size of the part.

#53 Muffler Hanger, Round 2

June 16, 2012

As mentioned in #44, I was not happy with the generic muffler hanger replacement part.  Ordered a real Volvo part and replaced the feeble generic one.  Fit and stretch are much better now.

Original broken part

Cheap generic replacement

Real Volvo replacement

$2.36

#52 Front Sway Bar Links

June 16, 2012

While inspecting the CV boots, I noticed that the front sway bar links were also shot.  Driver’s side was particularly loose and the boot is even coming off the joint.

Sway bar links connect the sway bar to the bottoms of the front suspension struts to provide stability when cornering.  They have joints at top and bottom to move a little but not too much.  When they go bad the car tends to tilt more and feel less stable when turning.  Bad links also tend to get very noisy, banging and clattering on bumps and uneven surfaces.

Old sway bar link is the vertical light-colored dogbone-shaped part.

Bought heavy-duty aftermarket sway bar links from IPD to replace the old ones.  These are more robust and should last a long time.  You can see how much thicker the connecting rod is and they have tougher elastic boots.

Both joints in both old links were very loose.

New ones are tight; they can be moved with a fair bit of force but not freely.

New heavy-duty sway bar link installed on driver (LH) side. Replaced links on both sides.

Performed this replacement when the drive axles were replaced (#51) because it was a convenient time to do it (working in same area).

Car feels a little more stable now while cornering.

2x $60

#51 Drive Axles / CV Boots

June 16, 2012

This is a big and important task.

Noticed a fair bit of rattling noise and vibration up front when driving and steering.  Visual inspection found torn boots over the constant velocity (CV) joints.  When the front end was raised to change the oil I got a better look at them.  Joints were really exposed and dirt was obviously getting in and grease getting out.  The RH (passenger) side was particularly bad and there was a lot of play and noise on that inner joint when the wheel was spun.  Driving in a tight circle also caused a clicking sound, which indicates outer CV joint wear.

CV joints are used on front-wheel drive vehicles where the drive wheels have to turn as well as move up and down with the suspension over road variations.  They allow movement of the wheel while transmitting engine power to the wheels from the transmission.  The complex mechanical joints are covered by a flexible bellows (boot) to keep lubricating grease in and contaminants out of the joints.  Usually there are outer joints at the wheel and inner joints at the transmission or half-shaft, which is the case here.

You can rebuild the joints and replace the boots but this is a lot of work and whole replacement drive axles don’t cost much more than the repair parts.  Besides, this is a labor-intensive job so it makes more sense just to replace the whole drive axle (axle shaft plus inner and outer CV joints).  Then it’s just a tough call on what parts to use.

Factory drive axles are very expensive, hundreds $ each.  There is a reputable shop which sells rebuilt ones good as new but shipping is expensive from New England (large, heavy parts).  Fortunately FCP in Boston had a good deal on decent EMPI brand drive axles with free shipping, which saved a lot of $$.

Replacement is not for the faint of heart so it helps to have some specialized tools, guidance and confidence.  First you have to loosen this nut, a 36mm behemoth securing the drive axle to the wheel hub.

You can use a long breaker bar driver with a 4-foot extension pipe but I went with my impact driver which made it quick and easy (but I had to buy the huge 36mm impact socket).

Lift the car, pull wheel, remove and hang the brake caliper, disconnect the tie rod end and control arm, then remove the nut and hammer the axle free, then pull the axle out from the transmission.  Passenger side is longer than the driver side because the transmission is on the driver’s side (left).

Driver side (short LH) axle separated from wheel hub, ready to pull from transmission.

Driver side axle now removed.

Driver side outer boot was split open and little grease remained. Not terribly contaminated inside, though. Still had a lot of play and noise in both joints.

Old and new driver side drive axles. Perfect match.

Driver’s side would not pull out freely; had to pry it out between transmission and inner joint.  Also had some transmission fluid leak out on this side because of the slope of the car and being slightly over-filled.

Passenger side (long RH) axle free from wheel hub, ready to pull out.

Passenger side outer boot was completely separated and lots of contamination got inside.

Old and new passenger side drive axles. Perfect match.

Passenger’s side is longer because it includes a straight half-shaft extension from the transmission out to RH side.  This side has a support clamp for the bearing which has to be removed.  This axle did pull out freely and no trans fluid leaked on this side.

New drive axles were installed and everything reassembled.

New driver side drive axle installed.

New passenger side drive axle installed. Half shaft to transmission shown.

New passenger side drive axle installed. Inner and outer CV joints shown.

Needed a helper to support the passenger (RH) side when installing the new drive axle.  On both sides you just push the end into the transmission with a little wiggling to get the splines lined up.  Took care that the axle end splines were clean and that the hub in the transmission was clean as well and that the seal was undamaged.

The nut that comes with these new axles is much smaller, only 32mm ;).  Tightened this big boy and all others to specified torque and pre-load position of the control arms.

Test drove at various speeds to make sure there were no strange vibrations.  Much smoother driving and steering now with new CV joints on both sides.

While working with the tie rod ends and control arms at the wheel hub, I saw that their joint boots were damaged and these items will need to be replaced in the future.

Replaced sway bar links at same time since I was in there.  Details in #52.

2x $105  Would have cost upwards of $1000 each if done professionally.  DIY !!

#50 Interior Door Trim

June 16, 2012

While replacing the driver’s door check, I had to remove the interior door panel.  This involved pulling the interior trim piece which is this trapezoid shape fabric-covered panel.

It was already weak and prying it out once more caused the thin fiber board structure to break in half.

A replacement part is not readily available and was probably expensive even if it were, so I repaired it myself.  Glued the fracture lines and spanned the break with four craft sticks which were also attached with Gorilla Glue.  Then clamped it while drying using a piece of scrap wood to keep it flat.

The fabric was also coming loose at the edges so stapled it back on.

The end result looks OK and is fairly stiff so it will do.

$0  The best kind of repair is free!

#49 Front Seat Height Adjustment

May 25, 2012

Took a while to get to this problem, which is unfortunate because it has been nagging us since we got the car and it is relatively simple fix.  Didn’t know how seat height adjustment should work and the main thing here was figuring that out.

Both driver and passenger seats in front were really low and the adjustment lever was not working.  Other controls worked fine on these manually-adjustable seats.  My other Volvo 850 sedan has electric seats so I haven’t had to deal with this before.

The lever is supposed to allow the front of the seat to move up or down when you push it down and raise or lower the rear of the seat when you pull the lever up.  Nothing happens when the lever is moved in either direction and we have all been driving around too low for comfort or good visibility.  This car is low enough to the ground already, so it feels like we are driving a go-cart.

Removed the passenger seat to diagnose the problem (to leave the car drivable with it removed) and found that the seat could move up and down with no weight on it when some force was applied.  What I discovered is that there are two gas springs in the seat which push up to raise the rear.  These are now 15-16 years old (factory original) and have weakened so they no longer provide force to raise the seat when the lever is pulled.

At this point we could just live with it since now we know we can adjust the seat(s) up and down, front and rear, while standing outside the car and moving the seat by hand while moving the lever in the appropriate direction.  Perhaps a lot of owners of older Volvos do this, especially if you don’t need to adjust them often, if at all.  But it’s not very convenient and actually hard to get them positioned just right using this method, since you have to keep getting in and out of the car to move and test the seat position.

Fortunately these gas springs are relatively inexpensive ($11+ each) so I ordered two for each seat and replaced them.

They are captive at one end and secured by a wire retainer at the other.  Removing the old ones is easy but installing the new strong ones was a real pain.  I’m guessing 50-75 pounds of force is needed to compress one so it can be installed between the two mounting slots.  Ended up rigging up my own cheap jig to pull tension on the far end using some 1/16″ wire rope and a couple of clamps.  My son helped push the far end into place while I pulled the cylinder compressed.  Definitely a two-man job.

Wire rope compression rig.

No doubt Volvo has some fancy compression tool for this.  Re-installing the locking wires is also nearly impossible but they really aren’t needed since these guys are very firmly wedged in place.

Old gas springs and retaining wires with key for size reference.

Now the seats move up and down in the rear as you adjust your weight on them and in front they go up or down by lifting or sitting hard.  Much like the modern office chairs with gas spring height adjustment, but with independent front/rear height settings.

The seats are fairly easy to remove with one bolt attaching the seat belt and four bolts securing it to the floor.  One precaution is to insert a safety blocking clip in front of the side impact sensor on the seat to prevent accidentally striking it with enough force to discharge the side air bag.

Orange safety clip prevents accidental side air bag deployment when working on/around the seat.

Having the seats out is also a good time to clean up years worth of trash and crud under and around the seats.  You will probably find some money, too!

This would be an expensive job at a dealer or independent shop because it is labor intensive.  DIY is the only way to go if you have help and can rig up a compression jig (or have super-strong arms).

4x $11.32  gas springs

#48 Door Prop, Round 2

May 20, 2012

OK, so the driver’s door is really annoying because it makes a loud pop every time it is opened and closed.  It was fixed from being loose and noisy way back at item #3 but since got so bad we couldn’t take it any more.

As suspected then, there is a problem inside the door check/stop where something is broken or very loose.

On many cars it is scary to remove the interior door panel because of hidden push-in fasteners and such but on this car it is typical good Volvo engineering and relatively straight-forward.  To get inside the door you have to remove the speaker, various screws and pry off a side panel, then pull the door lever off and remove the main door panel.

Once inside you have access to the door prop (goes by various names: stop, catch, prop, check).  It’s not the hinge, but an arm that keeps it from opening too far and helps keep it open when swung out.  Has a stiff spring in it that puts some tension on the prop when opened.

Inspecting the old door prop reveals no obvious problem, just old and worn.  Maybe a combination of wear on the arm and one of the bearings going bad makes the loud popping sound.  Removing the prop and installing a new one in the hole was actually a bit of a puzzle.  You have to fold the end hinge and twist it around sideways and orient it a certain way to get it all to move through the two holes, so some entertainment factor there.  Old and new checks are shown below.

Removed and replaced with a new part, sprayed some lubricant on the moving parts, then re-assembled the door panel.  Works like a charm and very quiet now.

$21

#47 Ignition Wires, Distributor Cap & Rotor

May 9, 2012

Like all gasoline engines, this car has spark plugs (already replaced) with wires that supply high voltage to each cylinder for fuel ignition.  There is a rotary high voltage switch called a distributor which is connected to the engine mechanically to synchronize the firing of each cylinder at the proper time.  The distributor cap and rotor inside it wear out over time due to mechanical friction and electrical arcing as the rotor touches the cap contacts.  The spark plug wires are not true conductors (they are fairly resistive) and they degrade over time (carbon migration, vibration and heat from the engine), as do the metal connections at the ends.

Replacing the wires, distributor cap and rotor are normal maintenance items for all cars equipped with them.  While there are no ignition problems on the car now, these parts need to be replaced before it starts to have problems such as rough engine, poor mileage, stalling and error codes.  Based on the date code stamped on the current wires, these are original factory wires (1997 Volvo was manufactured in 1996 and wires were made in the 41st and 43rd week of 1994) and are holding-their-shape stiff, so are long overdue for replacement.

Replacement is fairly straight-forward but to get to the distributor you have to remove the air cleaner which involves disconnecting some air and vacuum hoses.

One critical aspect of ignition wires is that the arrangement of distributor contacts to the respective cylinder must be maintained or the engine will not run properly, if at all (wrong cylinder firing sequence).  To make sure I don’t accidentally scramble the wires, I remove the distributor cap with the wires attached:

Cap and rotor don’t appear to be original but they seem to be many years old.  Rotor wiper is very pitted and worn (compare old part on left to new on right):

Bad focus on close-up but you can see more detail including the cracked arm:

and contacts on cap are very crusty:

Replace the rotor:

it is keyed so can attach only one way; no possible mistake.

Attach the new distributor cap:

Orientation guaranteed by asymmetric mounting screws.  New cap in place, old cap to right with wires still attached.

Remove spark plug cover from top of engine and pull the wires from the plugs:

Replace plug wires one at a time, following arrangement of old distributor cap terminals (cylinder number is stamped on cap so if I got them scrambled it would be easy to figure out where the wires go):

Used dielectric grease on connections and boots at both ends of each wire to ensure reliable contact and allow them to be disconnected more easily in future.

Replace source wire between ignition coil (high voltage generator) and distributor cap center:

Then put the air cleaner back in place and re-connect hoses to it.  Started engine to make sure it ran smoothly before re-installing spark plug cover on top of engine., making sure wires are secured in their respective feed-through clamps:

Wasn’t expecting much improvement since there were no real ignition issues, but the engine seems to idle and run a bit more smoothly.  No apparent difference in power.

$48.44 wires; $29.65 cap; $20.65 rotor; $1 dielectric grease

Shiny Red Fire Extinguisher

May 8, 2012

This isn’t a repair or maintenance item so doesn’t get a number but it is an important improvement.

Because my daughters will be driving this car I want to make sure they are as safe as possible.  So I got a special small fire extinguisher suitable for automotive use (electrical and fuel/oil fires).  Like the car it’s shiny and red.

Hard to find a good place to install it but I finally settled on a location where every seat in the car could get to it and it’s not in the driver’s way.  Screwed it to the back of the console between front seats.  It’s highly visible and ugly and I probably wouldn’t drill holes in a new car but hey, this one is 15 years old and not exactly a show car.

Hope they never have to use this fire extinguisher, but it’s available and they are safer with it.

#46 Transmission Flush

May 8, 2012

Automatic transmission fluid (ATF) is the life blood of the transmission.  The quality of this hydraulic oil is a major factor in transmission behavior/performance and longevity.  On this car the ATF was black and had a burnt odor, which indicates a lot of wear and contamination and some overheating.  Clean, fresh ATF should be a clear dark red color.  For all I know this is original fluid with perhaps some top-off over time, so this tranny really needed a flush and fill.

Started by adding a half can of Seafoam Trans Tune ATF cleaner through a dipstick funnel then driving a few miles at varying speeds to make sure it circulates through all the transmission gears and internal passages when warm.

Then disconnected the ATF cooling line at the radiator and attached a hose to a cheap measuring pitcher.  The flush hose came with a kit from IPD which also includes new O-rings and special hose clip.

I really like this Sterilite brand 1 gal. pitcher because it has large liter and quart markings and holds a full gallon.  The lid hole is just right to retain the hose and the pour spout works well to empty the full pitcher back into the empty ATF jug for disposal.

Ran the engine at idle to let the transmission pump 2 quarts of ATF into the pitcher.  The first four quarts were very dark and smelled bad.

Added two quarts of fresh ATF to the transmission through the dipstick funnel again and then drained two more out.  Repeated this 2 out/2 in until 16 quarts of fresh fluid had been added and the ATF draining out was clean and bright red.

Normally the flush can be accomplished with only 12qts but after 12 I thought we were still getting some dirty fluid out so went with another four.  Left 10 qts in the transmission which is the specified capacity.

Two surprises with the flush kit from IPD (which I still recommend).  First is that after flushing you have a long hose full of good fluid, perhaps a whole quart.  It took at least a half hour for gravity to drain it back into the transmission after hanging the hose up on the hood.

Second surprise is that the new retention clip with the flush kit to secure the transmission hose back to the radiator is cheap and brittle.  It snapped in two with only a small amount of force and you do have to really spread it open to clip in place.  Had to re-use the original clamp which is apparently better quality.  Getting the clamp on was actually the hardest part of this whole job, especially when dropped a couple times down into the engine compartment where I had to go fishing for it.

Checked for leaks after starting the car then drove five miles at varying speeds to put the transmission through all the gears.  Transmission now shifts more smoothly and quietly, which is to be expected.  It seems to have re-discovered 2nd gear, which it typically blew right through before.  After driving, checked ATF level with dipstick and checked for leaks again.

$7.99 Seafoam Trans Tune, $45 ATF, $24.95 Flush Hose Kit


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