Tommyd928

Hello savvy 928 guys,

I replaced the clutch on my '83 928S a few months ago (everything new from the slave cylinder, discs, plates and throwout bearing). Had a hard time figuring why it wouldn't disengage until I learned through this forum that I had to adjust the intermediate plate!

It was working great until today....I stripped the car for paint , drove it up on my car dolly (on the front wheels - usually load it in reverse to not scrape the spoiler and now I'm sorry I didn't anyway...).

I towed it to the painter aproximately 28 miles and when I was going to drive it off the dolly the clutch would not disengage. Has this happened to anybody else out there? Could the clutch become unadjusted for running in neutral for 28 miles? Is this possible?
Please help with suggestions or explanation...

Dave928S

Running in neutral would have only rotated axles and gears, and there would not have been any motor, clutch or drive shaft rotation. A normal clutch should not be affected by the attitude (uphill/downhill) of the car in any case.

I'm thinking that you may have some air in your clutch hydraulics, perhaps brought about or tipped over the threshold by the rear end elevation. 928 clutches can be stubborn mongrels to bleed and get every last bubble out, so you may need to use a few different methods.

Nothing broken under the dash? Have you had someone observe what happens under the car when you depress the pedal? Do you have altered pedal feel?

Tommyd928

Thanks for your input Dave.

I agree that there are no clutch moving parts in neutral. And the fact that it was in an upward position on the dolly for awhile made me think about lack of fluid in the brake /clutch resevoir and posible air in the line...I checked the level and it was ok but the pressure on the pedal was a bit light.

The wierd thing is that it goes into gear but the clutch dose not disengage. This thing was a nightmare to bleed! I'm going to take the tranny cover off again and check the clearance.

jon928se

Tommy

with the front wheels off the ground the fluid in the reservoir would be even deeper over the feed to the clutch m/c and shallower over the brake m/c feed. However to actually loose fluid out of the top end of either system you would have had to have the 928 upside down !

Unless some of the hydraulic pipe between the clutch m/c and slave just happens to have coincidentally spriung a leak at this time I suspect you don't have a hydraulic issue and the problem lies elsewhere.

How long had the car been sitting undriven before you towed it on the dolly ? If a long time it's possible the clutch friction discs are rusted to the flywheel or intermediate or pressure plate.

Dave928S

Jon .... I'd contempleted that it might have rusted or jammed from just sitting, but the OP said it was 'working great' and he 'drove it onto the dolly' .... towed it 28 miles and it wouldn't disengage to 'drive it off the dolly'.

I was thinking that a bubble already in the system may have migrated to another part of the system to give a more significant symptom, or something in the under dash linkage coincidentally broke or jammed.

Strange problem.

Fogey1

Like the NSA I figure more info is better than less, so here's a dump of all the clutch threads I've noted over the years. (Get it? A clutch dump ;-) I hope something will help.


https://rennlist.com/forums/928-foru...d-bubbles.html
Bleeding clutch and bubbles from Wally

https://rennlist.com/forums/928-foru...-properly.html
Please help me get this clutch working properly!!

Originally Posted by SharkSkin
I have some info on the clutch here that may help you understand the mechanism and how to adjust it.
http://members.rennlist.com/sharkski...oryOfOperation

https://rennlist.com/forums/928-foru...s-way-out.html
Help. I think my transmission is on it's way out.
It's started about 3 months ago. It grinds a little almost evertime I shift into 2nd unless I'm real careful. Also if I don't shift into neutral I can't get it out of gear once the car stops at a light and don't want to force it so I have to clutch start in 3rd and 4th sometimes.

https://rennlist.com/forums/928-foru...ch-owners.html
Something useful for duel-disc clutch owners. PIX

https://rennlist.com/forums/928-foru...ment-pics.html

https://rennlist.com/forums/928-foru...ml#post9032935

https://rennlist.com/forums/928-foru...c-problem.html
Clutch Hydraulic Problem

BMW, VW, Porsche Clutch Bleeding

https://rennlist.com/forums/928-foru...djustment.html
I have MASTERED the twin-disc adjustment!

Tommyd928

Thanks Fogey1.. I have trouble finding related past threads.

I'm going to check the adjustment on the intermediate plate tonight. I can't imagine it being an air bleeding thing since it's engaged and won't let go of the gears, and not that it won't engage.

I'll post my findings tommorrow.
Tom

Dave928S

I've re-read all this and I'm wondering if the intermediate plate has 'adjusted itself' backwards with the vibration and bumping during the tow, and clamped the rear disc. When mine was giving me trouble it was always clamping and not letting the rear disc go, and that was the disc that was most worn. The 'H' adjusters on my intermediate plate were sloppy and letting it move out of adjustment too easily.

Here's another thread with a lot of discussion on adjutment, but also a remedy to stop the adjusters moving by replacing the rivets (which get loose) on the intermediate plate with a bolt, nut and spring washers. I've used that fix on my intermediate plate. ..... https://rennlist.com/forums/928-foru...f-into-18.html

I think that replacing the rivets with the bolt, nut and spring washers is the best and neatest solution, and it allows adjustment later if you want, but Mark Kibort has locked his at the correct adjustment position by drilling a small hole and pinning them.

You'll find heaps of other threads to wade through if you search 'intermediate plate adjustment'.

Tommyd928

Thanks Dave. I'm going to pin them like Mark Kibort suggests...don't want to take the whole thing out again.

I'll keep posting on my progress.

Cheers,
Tom

Dave928S

What can also influence the plate position, and make it more resistive to returning to a neutral non-loaded position, is a worn stub shaft (and lack of correct lubrication). It can get wear on the splines which can leave a ridge. Here's a pic of one where you can just see the beginnings of the ridge that forms (marker line). If you ever pull the clutch pack out this would be one of the things you would look at.

As it worked OK before it seems likely you'll get it right with IP adjustment.

Tommyd928

So I went to adjust the intermediate plate this afternoon but everything seemed fine. I opened up the clearance on the brackets from 1mm to 1.5mm. BTW, stupid thing that the factory manual in the explanation says "this will produce a gap of 0.7 to 1.0 mm or 1.2 to 1.5 mm (see sketch). when is it .07 to 1.0 mm or 1.2 to 1.5 mm? It dosen't say??

The car was on jacks stands in the front so my friend the painter who was helping me said we should just lift the car in the back too to see if the wheels turned to not have to take the front down. This was meant to happen because it turned out the problem wasn't the clutch, it was the drivers' side axle that was completely loose and resting on the exhaust pipe!

Seems like someone had messed with it before I bought the car and hadn't tightened it properly and it went loose while I was towing it to the paint shop.

Tommyd928

Thanks everybody for posting and sorry for dragging you on the wrong side of the problem.

I was pissed at first, then felt happy I had found the problem and lucky the axle hadn't got stuck somewhere on the body or dragged on the pavement on the way to the shop. I was comfortably resting and spinning on the exhaust pipe!

I was able to put it back on the transmission with two bolts (the rest got bent) to move it around for now and I'll also have to pack the joint with greese and a new boot that got shredded.

I'll post a picture tommorrow can't seemed to upload it from my Ipad.

Thanks again, you're a great group of people,
Tom

Dave928S

OMG!!! .... you had the potential for a BIG disaster with a disconnected axle. You definitely need to go over everything on that car to make sure there are no other nasty little surprises waiting for you ... before you drive it again.

Whoever left that axle like that needs a really good **** kicking!

depami

Glad you found it and it's fairly simple.

Would this car have moved with LSD?

Dave928S

Yes .... if the rolling resistance was less than the LSD setup torque ... no handbrake, no wheel chocks, no bump or incline, etc, etc.

Tom .... check your fuel lines!