96 850 judders while braking and accelerating/coasting

[theobviousfaker]

Hi,

my MY96 850 (B2525S (NA), manual transmission FWD) has been juddering for at least a year now. It happens mainly under light-medium braking. The frequency of the judder ist speed dependent, its starts to get really bad from 70 mph upwards, but you can feel it at all speeds. Under hard braking the judder gets less or is even gone completely. You can also feel the judder in the steering wheel as a left-right movement.
I suspected warped brake discs for a long time, but did not bother to change them as they were new when I bought the car (and money is a constraint).

Also, seemingly unrelated, in 1st and 2nd gear the car judders forth and back while acclerating smoothly or coasting at very low speeds/low rpm. The clutch is still ok, I know that because I had to replace the RMS seal a year ago (and silly me didnt replace the clutch, because I didnt knowI could do that all in one go .. *facepalm*).

Yesterday when I changed my tyres I noticed the front-right outer CV joint boot is torn and it has already flung out some of the grease. It wasn't torn last time i checked (around 2-3 months ago welding the exhaust pipe).

Now the car has also some front-right damage history.. i bought it with a bent fender, somebody probably hit a pole while parking. The car was driving to the right, i had to hold the steering wheel some 45° to the left to go straight. I had the suspension checked by a Volvo mechanic with good reputation a year ago and they didnt notice anything (although I myself wont go there anymore.. they overcharged me grossly on brake fluid and the overall experience wasn't so well, since they didn't find any problem and had no suggestion what to do about it).
The suspension was also aligned very well (different shop, I have the printout before/after) but it will still go slightly to the right, steering wheel is about 15°-20° to the left when going straight.

Now that juddering from braking wasn't there when I bought the car, it developed later. I cannot pinpoint that unfortunately, but it coincides with me driving the car into a ditch... with the right hand side of course. Wasn't so bad, nothing obviously cracked, bent, failed and the car didnt drive any more crooked than it had before. But I did hit the bottom of the ditch with the front right wheel, not too bad because most the car's weight was supported by the cars underfloor (but the right wheel was locked in place, diff sent all power to the left wheel which was freewheeling).

Now that the CV boot is gone anyway I want to repair that suspension for good. I want to leave out changing the brake discs first, I don't think they are the culprits (no juddering under hard braking, also they have been checked and bled properly).
I read that if the outer CV joint is gone, you can feel it in the steering. I have to check that, but I don't really remember juddering/clunking while cornering.
Haynes manual says, juddering under acceleration/coasting comes from worn INNER CV joints - can that be confirmed?
I also read here in the forums that a bent tie rod could be the culprit. I heard the mechanic who aligned the car mumble about that, too. He wasn't sure why the car is still turning to the left, so he mentioned "maybe a bent tie rod butnotsuregottagetbacktowork". EDIT: Maybe he was talking about the steering rod? I'm not sure anymore..

Soooo... what I couldn't find is how to check CV joints. Can that only be done while driving and "feeling" the symptoms or can you crawl under the car and "jiggle" them to see whats up? Can one feel a worn out CV joint like you can feel a worn out bearing? If so, how to "jiggle" it to feel that?
The tie rod never looked like it was obviously bent, but maybe the heads crooked or something. A new replacement tie rod is cheap, I'm willing to change it alongside the CV boot anyway (the shop says "tie rod head", translated from german. Theres a photograph- is that the "whole" tie rod?).

Whats the best way to handle that - just get a complete replacement right hand axle with both CV joints (with my financial situation, I'll tear one out of a scrapyard-car)? Or try my luck with replacing one of the CV joints, tie rod, or whatever part I didnt think of yet?

Ah, another hint: The tyres don't seem to have any different left-right wear pattern. Can some parts be exluded from the list of suspects because of this?

Sorry for the long rant. I have been thinking alot about this lately, as I am at the verge of either repairing the car (if possible) or selling it otherwise. I love the car. But the above conglomerate of problems, which seem very related, is making me pull my hairs by now. I have spent many relaxing nights in that car in many different countries, and I would like to keep it indefinitely. Theres no corrosion anywhere and the engine is in perfect condition. It has only 185k miles on it now feels like its good for another 180k miles.

[jblackburn]

Replace the whole right-side axle and see if it goes away. Evaluate from there. Sounds like a bad inner CV joint to me - rebuilding on your own is usually a difficult task, if you can even find quality CV joints.

I would recommend R-axles. http://www.raxles.com/

Hopefully that will take care of most of the shaking - that is what sounds most likely based on your description; there may still be uneven pad build-up on the rotors that may not shake on heavy braking. If you're short on $, resurfacing them is a good option.

[scot850]

Welcome to the forum!

There are many things that can cause the issues you state, but a good/positive point you make near the end of your note is that the tires don't appear to be wearing un-evenly.

I'd suspect you have a few issues going on:

1) Brake shudder/pilling to one side - When braking, or even all the time - Check all the brake calipers are working correctly and are free. Fronts are prone to seizing, as can the rears. Check the pad condition. You may find one that is lower on one side of the disc than the other pointing at a sticking caliper. Also check that your rear parking brakes are good. Pull the rotors and check the shoes haven't failed and that the cables are free. The cables tend to crack where they are bolted to the rear axle frame and then they will drag, wear down the shoes, and cause a vibration. Rear shoes can also de-laminate and jam in the rear drum.

2) Broken C/V boot - Replace ASAP! If it has been like this for some time it may be toast. If you are lucky, it may just need new boots and grease. I'll let one of the more experienced guys tell you how to figure out if it is worth fixing. When a C/V starts to fail, you can get vibration at all speeds, particularly when accelerating and decelerating when the load is off the bearing. My one suggestion when replacing is use OE/Volvo where possible. I'd rather use a good used OE over a new re-built unless you know some one with a good reputation of re-building. I had a brand new re-built front axle that was bad from day one with vibration, particularly when accelerating. Obviously, when you pull a used one, check the boots are flexible and un-cracked before pulling!

3) If pulling to one side is not fixed by these issues then you may have a bent steering arm or worn control arm/ball-joint/inner or outer track rod or steering rack issue. You could also have a bad upper spring seat/bearing on one side. Jack the front of the car up and turn the steering. Is it tighter one way or the other? Also you could have worn rear axle supports (forgot the correct name), they can also cause strange steering issues as the car is steering from the rear.

Hope this gives you a start, but don't be afraid of all the possible issues. All could be caused by only one or 2 issues.

Good luck!

Neil.

[theobviousfaker]

Thanks for your answers so far!

I found some used right side parts from a guy who ripped his whole car apart (engine died). Whole right-side axle, and then some (control arm, etc). Some parts even as-good-as-new. I will probably give that a shot, way, way, cheaper then getting a new axle alone (around 300-400 Euros here).
As for the brakes, hard to find a shop around here which does resurfacing. Since two new quality discs and pads are about 160 Euros, I understand why. But every euro counts for me, right now.

As for checking the rear and parking brakes.. I will give that a shot as well. I have limited access to a workshop with a lift, but time is an issue there. Will probably take a few days.. I'll update the thread.

As for CV joints, really no method for checking them manually?

[theobviousfaker]

Now I just found out, that there is actually good advice on how to check for various components of steering and suspension in the "general tune-up" part of the Haynes Manual. Basically, rocking the wheel without and with the brakes depressed, grabbing the wheel at 12/6 o'clock, and 3/9 o'clock. I didn't expect it in that part of the book to be honest. Will get back with more information..

[jblackburn]

Now I just found out, that there is actually good advice on how to check for various components of steering and suspension in the "general tune-up" part of the Haynes Manual. Basically, rocking the wheel without and with the brakes depressed, grabbing the wheel at 12/6 o'clock, and 3/9 o'clock. I didn't expect it in that part of the book to be honest. Will get back with more information..

That will let you check the tie rods and wheel bearings for play. I can't really think of a test for an inner CV joint short of the car shaking side to side when under acceleration; the outer one will clack on tight turns but there isn't really a test for play in a inner CV joint with it in the car. You can rock the wheel back and forth, but the parking pawl in the transmission will move back and forth, and the CV joint will normally have a little bit of give back and forth too.

[theobviousfaker]

Today I checked wheel bearings and tie rod via Haynes' instruction. No play whatsoever. While I was at it, I instructed my assistant to only slighty brake the wheels and I could feel a changing resistance while turning the right wheel. The left one felt consistent. So a warped brake disc just got more likely.

The outer CV joint still seems to be ok, no noises or anything while turning.
As there is no test for the inner CV joint, I will most probably try to change to whole right side axle anyway. I can get my hands on a cheap used one and its probably less work then changing just the CV boot.
@jblackburn: When the inner CV joint fails, why should the car rock left-right? To my understanding there would be radial play when worn, not axial. Coasting/accelerating in low gear makes the car rock front to back, the brake juddering actually translates into a left-right shaking that I can feel in the steering.

There's also no free play in the steering. Although it feels very mushy, there is no lost movement.

A more thorough check of ball joints, etc will be done later. I only had the car on a small jack, no chance I am going to crawl under that

I also checked the upper torque mount of the engine. There is a little tear in it, as can be seen on the picture. But it is in the indented part of it, where it seemed to be only paper-thin anyway. To me, it looks ok. What say the others? By rocking the engine, nothing really moves out of proportion, so I'll rule that one out.

[theobviousfaker]

Now that all those pesky holidays passed and a less-used-then-mine right driveshaft finally got through the mail, I swapped it today. Turns out, both CV joints on the right side were shot! Not badly yet, but still.
Took me about 2 hours, mainly because I snapped a bolt and had to use a torch and a more experienced and stronger man to punch it out.
One nice thing to note: If you remove the right driveshaft, there is no oil dripping out of the (manual) transmission/differential! That is, the oil level is below the rightside shaft hole (I recently flushed it with new oil, so its filled per spec).
I also changed the control arm (luckily, because the torch-action burned the ball link on the original one).
Unfortunately, the car still veers slightly to the right. On the way home it felt like it was less then before, but that might just be wishful thinking. Coasting and breaking seems smoother as well, but it was just a short trip home so I am not sure yet. The rotors are still changeworthy, there is lots of brake pad imprints and pad residue visible on the discs. After what I have read here (a link I found here on MVS) I think its pretty obvious that my rotors are goners.

One more thing I have already read in advance here on MVS but didn't think of to ask before buying the new driveshaft: The "new" one had a smaller thread size at the end, so the original hub-nut didn't fit. The smaller one was not included... but being in a workshop, a different manufacturers nut fit.

[E Showell]

Faker -- You mentioned landing in a ditch a while back. If you're using alloy wheels, is it possible that one of the wheels is slightly bent/out-of-round? That might cause the symptoms you describe. Worth having a tire shop check so that's one more thing you can cross off your list. . . .

[Cees Klumper]

Good thing you replaced the drive axle. Skandix (in Germany) does sell a new inner CV tri-pod bearing for €25 for future reference. Donn't rule out the engine mount as a possible contributor to your symptoms. If it's not too expensive I would replace the damaged ine if I were you. Also check the strut mounts and bearings as I understand they can cause vibrations etc. if the brake pads are still ok you can just replace the discs for less than €100 a set I would think if you shop around a bit, there's so many choices also German made. And 2x on checking the straightness and roundness of the front wheels. Good luck and keep us posted.