AndrzejMi

I thought I'd document my clutch replacement for my 1980 928 as I'm sure it'll reveal some complications along the way, and perhaps this will help other owners in the future.

The story began with a slight squealing noise whenever I used the clutch pedal, to me this meant that I'd need to get the release bearing replaced and I'd get the car booked in for the job. I had however already booked in and paid up for a track day at Castle Combe, about 60 miles away from me. I did the day, all went really well, except the journey home. The squealing suddenly got a LOT worse, as did the traffic, which made it more challenging to not change gear. I wasn't too keen on doing too many clutchless changes either so as not to risk damaging the box. Anyway 4 miles from home the clutch pedal, when pressed, suddenly sprang to the floor. I popped it up, but it was now stuck in that position. Still too much traffic to get home without breakdown help.

I have the car at home and am going to get the car up on a ramp to take a closer look next Monday as to what's actually happened, but of course, I've been doing some reading & research. I also had some issues, such as pulling away judder (especially in reverse), and a rattle when in gear. So I thought that whilst the release bearing was going to be replaced I should replace the other clutch parts. First off they're not cheap. Here in the UK I found the most competitive prices from www.porscheshop.co.uk for OEM Sachs parts. I went for their 1980 Clutch kit, a release bearing, a pilot bearing, and a fresh set of 9 bolts. The intermediate plate seems to be unavailable, anywhere - except if I spend a lot more for a 928 motor sports upgraded version. Fingers crossed that mine will be in good shape!

These took a few weeks to arrive, the pressure plate looks as expected, an original Sachs part in an original Porsche box. But the bearings, and the clutch discs led to further questions...

1. The clutch discs were the same. This was a surprise as when I was looking around for the best prices, the front and rear discs were coming up as different parts. I sent an email query to PorscheShop, but they assured me that this was correct (due to a surface upgrade) - hmm I'm not convinced. I'm particularly worried that the length of the splined centre won't be correct. Does anyone have any experience of this? Here's what they sent me:



2. The release bearing has rubber pads on each side. I dug out the Workshop Manuals and I spotted that there was a parts change during the 1980 model year production where the bearing had these pads to reduce vibration noise, and also to stop outer case spinning. So this sounds great I might have the earlier version so this is an opportunity to upgrade. The snag is that if I do have the earlier version I'll also need to upgrade the arm, the ball stud (from 10mm to 19mm), and perhaps the shaft too... at least the later version parts are available...

3. Finally the pilot bearing. It's a cheap part, but it seems to make sense to replace this whilst the clutch is out, besides my judder could have been caused by some leakage and contamination from a bad bearing? My worry is that the supplied bearing doesn't look like it's of the highest quality:


Does anyone know if this will be just fine, or am I just being paranoid?

Anyway, that's where I am so far.. next instalment will be on the 22nd, when I can get a good look at what's on the car right now...

Andrew Schauer

I too just finished a clutch replacement on my 1980 model. I chose to upgrade the pilot bearing to an NTN brand, for the same reason... easy to do now, much harder to get to later.
You may want to consider one of Precision Motorworks' upgraded short clutch shafts as part of your project. Best of luck!

Andrew

AndrzejMi

Thanks Andrew, I'll take a look at that & find out what Motorworks are offering. I'll definitely be looking into the pilot bearing. I don't suppose you have the part number that you went with for the TNT bearing?

Petza914

You'll need to have some bent horseshoe clips on hand to put under the adjustment Ts to lock the pressure plate in a position that let's you get it apart and then back together. Don't overgrease the splined shaft as it will sling grease onto the friction surface and make the clutch slip - ask me how I know.

The two friction discs with the same hub design will work fine.

Mark all the clutch pieces with a paint line before you remove them so you can put anything you're reusing back together in the same balance relationship they have now. The new clutch discs should actually be marked with a balance mark on them too. Those two marks should be installed 180 degrees opposite each other.

There are lots of clutch pictures and info in my recent Blown / Damaged head gasket thread.

Wisconsin Joe

The WSM has good instructions on this. Section 30. As Petza noted, you need to make 'U' shaped shims that go under the rivets on the pressure plate pack. They keep the springs compressed some so you can get the pack apart once it's out.

If your 'squealing' sound was only when you pushed down on the clutch pedal, it was likely the pilot bearing.

The Throw Out Bearing (release bearing) spins all the time. The pilot bearing only spins when the clutch is released (pedal down).

The TOB itself is simply pressed into the housing. So you can reuse your old housing with a new bearing.

Can't say for sure about the quality of your pilot bearing, but keep in mind that it only spins when the clutch is released (pedal pushed).

When you have it apart, check your intermediate shaft. If the splines aren't smooth and even, it will cause problems.

Last, but certainly not least, did you get in touch with Roger at 928s R Us? He has all the right parts, including 'just the bearing' for the TOB. He ships to the UK on a regular basis.

928#00076

I'll refer you to this thread which details some issues I encountered recently in replacing the clutch in my '78. Mine is a very early serial number so some of your parts may be different. The P.O. had already replaced the ball and fork on mine which was nice. I am now about 300 miles on the last reinstall and still working okay. The "matching" clutch disks did not seem to work for my setup. Hopefully they will work for you. You need to pay close attention to adjusting the three "forks" on the intermediate plate.

https://rennlist.com/forums/928-foru...+clutch+advice

AndrzejMi

Hey guys - I really appreciate all of your advice postings. I'll certainly be giving Roger a call then. Fingers crossed that I've got the slightly later 1980 configuration so that the matching clutch disks do the trick..

Thanks

By the way, does anyone have a specification for the pilot bearing? I'm still of the mind that I should go for a decent quality one as it's such a low cost part given the size of the whole job. The one I received has 6002RS marked on it but I've read elsewhere that it's a 6020..

AndrzejMi

Also, if it was the pilot bearing that failed - what do you think happened when the pedal suddenly sprang to the floor on pressing it? (And after popping it back up is stopping it move down at all?). I know I'll find out on Monday when up on a ramp :-)

AndrzejMi

Well I didn't manage to get a look at the clutch today after all. Backlog of work at the garage - am trying out a local place called Chelsea Carrera in High Wycombe, UK. They're only 4 miles away and I really value the ability to pop in and see / discuss the steps ahead. They've got a backlog of 911 work to get through which means mine won't get onto the ramps until Thursday if that all goes to plan.

AndrzejMi

Got to have a very quick (finally). It was pretty clear what had happened. The release bearing failed and had driven into the fingers of the Sachs pressure plate. Broken fingers and bearing parts dropped out on clutch cover removal. Luckily the clutch fork is of the late design so don't need to update it, and my biggest relief was seeing that my intermediate plate was in really good shape.

So clutch kit, new bearings are all ready to go in and it looks like the only additional part I need is a new guide tube as mine looks very worn. The splines on the intermediate shaft look to be in pretty good shape so leaving it as is, especially as no one here (UK) appears to have one in stock.

Will see it again tomorrow and hopefully remember to take some photos.