Adam C

Hi Guys,

I seem to have developed a strange clutch noise in the car. I don't think it is SC related.

Noise is a grinding type rubbing sound, present only when the clutch is engaged. With the clutch depressed, the noise goes away.

According to service records, clutch was replaced by PO less than a year ago, albeit at a Lambo dealership.

Clues?

worf928

Throwout bearing. (My bet)

Do you have records on exactly what was replaced with the recent clutch service?

Adam C

Hi Dave,

Yes I have records and will check. I am fairly certain the bearing was replaced.

deliriousga

I'm with Dave, Release Bearing is probably the culprit. Any light squeeling noise with that?

I'd check the receipt from the Lambo place and see if the Release Bearing (AKA Throwout Bearing) was replaced or just a new clutch disc. If it was just the clutch disc, you'll want to put a new release bearing and pilot bearing in and maybe replace your rear main seal while the whole clutch is out. All of those bearings will go out over time so you might as well put new ones in each time the clutch is done.

Chris

Be warned, if your clutch is original (just new friction disk) then the throwout/release bearing for that system is NLA. Nice ... with the newer bearing you need a new guide tube and release arm I think. Need to check with suppliers.

Chris

worf928

The reason I asked about which SPECIFIC parts were replaced was that if the release/throwout bearing was replaced and the release arm lever and guide tube WAS NOT replaced then THAT IS the problem.

The only new t-o bearing available AFAIK is the GTS spec bearing. This has been the case for many years. The GTS spec bearing has a different inner diameter and a different mating surface for the release arm lever - and thus the requirement to change all three.

If a GTS t-o bearing is used in place of a pre-GTS bearing with the pre-GTS leaver and tube then the result will be horrible-sounding nasty noises.

The difference in ID is only 1mm - but that's enough.

worf928

True. But, if you have the wrong release arm and guide tube then you can get some nasty noises.

deliriousga

That reminds me, if the three parts mentioned above have to be replaced, your job gets to be a real pain because you also have to replace the ball stud that the clutch arm pivots on. The new ball has a 10mm stud which is much larger than the original. Somebody please chime in if the ball itself is the same size as the original ones. That means the bell housing has to come out to drill out and tap the new threads. Also, add the clutch arm bushing if it wasn't done. That's what angles the release bearing and causes it to wear faster.

With my clutch, one of the PO's mechanics replaced the arm and stud, but had the old style release bearing and sleeve in it. Like Dave said, that 1mm makes a big difference and it wore my release bearing out.

deliriousga

These are for the '87 up single disc clutches:

Release Bearing: 928 116 085 08
Guide Tube: 928 116 087 16
Ball Cup Bushing: 928 116 145 03
Ball Pivot for Clutch Arm: 928 116 075 01
Release Arm: 928 116 832 09

Adam C

Wow - thanks guys. I will dig out the part numbers. I seem to recall a discrepancy way back in what was replaced but I will check.

Sterling - what does torque tube bearing failure manifest itself as?

Regards,

Adam

deliriousga

I haven't had this happen, but from what I've read here previously you'll hear the grinding or whining sound you're talking about from somewhere between the back half of the door and the rear of the car. You should still be able to hear that sound when the car is idling in neutral with the clutch pedal out.

Dennis K

I agree with the above, throwout bearing.

Does the noise stop if you lightly press on the clutch (not enough to engage it)?

Adam C

Dennis - yes, more or less. It definately changes tone and stops altogether when the clutch is depressed.

worf928

John, are you sure? I've not once run across a reported issue with the ball stud - on S4s. (Perhaps it's a problem with pre-S4s?) The release arm, bearing, guide tube requirement is in at least one Porsche doc.

Also, I upgraded my '89 GT to the new spec and had no issue with the size of the ball stud on the housing.

EDIT: Perhaps the stud-size difference is taken care of by the bushing...

I'll need to find the Porsche doc...

EDIT: '93 Service Information Technik book lists the release bearing and guide tube. No mention of the release arm or bushing. Still looking...

PET shows the bearing superseded with a new bearing and tube. The tube is superseded with a new tube and release arm. Bushing and ball stud look the same for all S4 years.

deliriousga

I had been told that by the folks I bought the clutch parts from. Maybe they were mistaken with the model that needed the replacement and that's why mine was ok. I just thought I got lucky.

I have the AllData DIY subscription and I just checked it. It has the same info you have, clutch arm, release bearing and guide tube, but doesn't say anything about the ball stud. The FSMs have the progression of the ball stud size change, but I don't have those here to look up what it said.

Sorry about the confusion.

With the bushing, it just needs to be replaced when the clutch is done. Mine was non-existent when I pulled the arm out. The ball had ground a pit in the arm so I had to replace it too.