850R manual Clutch (?) shudder
 

Hi folks

I'm new to this forum so apologies if this question has been addressed before. I have recently purchased a 96 850R sedan with about 85k miles on the odo. Generally in good condition with a known history.

To eliminate a heavy and noisy clutch (thrust bearing) and a shudder on initial clutch pick-up, I have had the clutch replaced (M/C flywheel, new pressure plate, new clutch plate, new thrust bearing). Work done by a Volvo specialist. (And a new rear main seal as a precaution!)

The clutch plate and pressure plate that came out were well worn, but not RS. They told me that the flywheel showed some signs of hotspots on the wearing face - that were machined out.

Clutch feels great now, but shudder persists. I need to feed in about 2000 rpm to get it away smoothly. Shudder can be felt on up-shift and downshift too, when engaging the clutch. The shudder is quite severe, and feels the same in forward and reverse gear. There is no clutch noise associated with the shudder.

The guys who did the work have since looked at the mounts, and their initial comment is that the mounts are OK. The car is going back in for a more detailed exam next week (maybe even to excavate the clutch out of the bowels of the engine/trans assy), but I thought I would check to see if anyone has had a mystery shudder traced back to anything unusual. There are no too many 850R's around here so there is not a great deal of experience with them.

Any comments appreciated.

Wolfgang Mika
Melbourne, Australia

RE: 850R manual Clutch (?) shudder
 

My clutch emits a slight squeal on pickup, but with no shudder and it will take at sensible revs.

The supplying dealer told me that R clutches tend to make this little noise due to their type - a "competition" spec to take the extra power.

Your R has about twice the mileage mine has, but shouldn't have totalled the clutch unless misused.

Check that the replacement clutch is for a R, and not for the T5 manual.

RE: 850R manual Clutch (?) shudder
 

Hi,
For what its worth .... I drive a 940.. different clutch thrust but smilar plates. My experience is as follows. Clutch juddered and squeeled so replaced the clutch and then had worse problems. Turned out to be a slight misalignment of the thrust bearing. The self centering bearing did not self centre so juddered and rattled. Secondly my 940 and I belive the 850/v70s have a hydraulic flywheel.
This means that the flywheel is in to halves and they are sprung against each other. How I dont know. This eliminates the need for springs in the clutch plate itself. I had never seen this before and it took some woking out but details can b found somewhere on the net on sachs/boge sites. If for some reason, debris,dust etc. the two halves of the flyheel were not free to rotate against each other there would be no action for springing the clutch due to no springs in the friction plate. I wonder if the right bolts hold the clutch driven plate on? If the bolts were to long thy mightgo from the fron flywheel to the back flywheel and lock the hydraulic action. Or it could be a faulty flywheel (expensive around £220+vat I think.) To test the flywheel its a gearbox off job then by tightening up the clutch bolts there is a springy feel before the engine turns. Cheers Nige

RE: 850R manual Clutch (?) shudder
 

Simon

Thanks for your comments. My new misbehaving clutch makes no abnormal sound, apart from the motor banging around inside the engine bay. By sensible revs, I assume you can drive off gently, keeping the engine almost a idle with light throttle.

The service guys know that the "R" has a beefed up clutch, so I expect they would have got the right bits. They mentioned that they were genuine volvo parts, so there shuld be no question about basic quality.

The old clutch was not really totalled. Obviously worn, but the real problem was the trashed thrust bearing and the shudder. Driving the car before the new clutch was fitted, one would jump at the conclusion that replacing the clutch and machining the flywheel would have everything back to normal. That's the worrying part.

I will double check next week to see if the right parts were fitted. However, the thought also is whether a "weaker" clutch would have a shortened life and (possibly) slip because of the power output. I do not know whether thre are any other differences between the parts that would cause a severe shudder from new.

It leaves me to think that the only options are (1) something badly wrong with the engine mounting (2) the flywheel machining was inadequate or (3) the new parts are faulty.

One curious thing is that, for the first couple of uses from cold, the clutch is almost OK, with only ahint of shudder. As soon as the engine warms up, the clutch plays up. Suggests that heat (not necessarily clutch temperature alone) plays a part. Hmm...

Regards
Wolfgang Mika

RE: 850R manual Clutch (?) shudder
 

Hi Nige

As the thrust bearng was replaced when the clutch was renewed, there is always a possibility that this was incorrectly installed or did not seat properly. I will mention this when I take the car back in. However, I would expect that if this were the problem, the clutch would misbehave 100% of the time, whilst mine seems almost normal (at least, a LOT better than wjhen everything warms up) for a minute or so when stone cold.

I confess I did not look too closely at the pressure plate, as it looked like a normal diaphragm type pressure plate. My guess would be that my 850R has a "normal" clutch. I don't yet have any repair or service manuals for the car.

Rgds
Wolfgang Mika

RE: 850R manual Clutch (?) shudder
 

I have a 94 T5 and the amount of clutch shudder seems to depend how slowly I let it in. Slowly feeding in the clutch for a smooth sensible launch gives a lot of shudder , but a more positive and spirited launch gives no shudder at all .

The particular rumour I heard and believe is that a beefier clutch was introduced for the T5+ but this gave a shudder issue - so the std clutch is now specced as a replacement as it handles the power ok anyway. When we tried to buy a new clutch for a T5 at work this is the story we got ...

All the best

Dr D

RE: 850R manual Clutch (?) shudder
 

Hi again. One tiny point worth loking at...... What sort of flexi coupling have you got on he exhaust? Does it tighten up by any chance as it gets warm causing a rigid engine/exhaust which could cause non flexing of the engine on take up.......solutions are often in the wierdest places!!!! Cheers Nige

RE: 850R manual Clutch (?) shudder
 

Hi Nige
Short answer - I don't know - I have seen a braided flexible section down behind the turbo but I do not know th details. Generally, my feeling is that a shudder would come from too much flexibility rather than too little - but I am prepared to be corrected on this...

I took the car back to have the aircon regassed this week and to (hopefully) look at the clutch problem. Unfortunately, no progress was made on the clutch as they could not find anything external that seemed to be causing the problem. At the time the clutch was done a couple of weeks ago, a second 850R had a clutch replacement at the same shop and this went well, so I believe I can get it fixed. The only real difference between the tow was that my flywheel was re-surfaced whilst the other one was in sufficiently good condition to leave "as is".

At this stage, I will live with it till after x-mas and then take it back in. In the interim, the shop is going to explore possibilities with Volvo to make up a hit list.

I continue to be reluctant to have the clutch removed again on the blind hope of fixing the problem - it is too expensive an exercise for this!

regards
Wolfgang Mika

RE: 850R manual Clutch (?) shudder
 

Symptom sounds similar.

My basic thought is that the clutch *should* operate without a hint of shudder, so if it does it there is something wrong. I would be happy to live with lower spec clutch parts if this resolved the problem. However, I am also haunted by the fact that a second 850R was done at the same time as mine and it came out perfect.

I can't get rid of this nagging feeling that the clutch is not the root cause of the problem.

cheers
Wolfgang Mika

RE: 850R manual Clutch (?) shudder
 

I'm getting a lot of judder on my V70 - have you checked the engine mountings, particularly the top one as this fails about every 20000 miles and is a known problem.