That is how I'm starting to understand it:

The T-Adjusters should only move then the metal "springs" are pushed to capacity. This will "adjust" the T-Adjusters to take up any slack caused by disk wear.

So if Jim is correct and my front disk is stuck to the flywheel, my T-Adjusters are being pushed all the way forward trying to find the front disk. Once they reach this point, nothing in the system is going to force them back, causing the floater disk to never disengage from the front disk / flywheel cluster f*ck.

All of this is happening in a space no larger than a few millimeters, simply amazing.

A friend of mine worked on an early 928 where he found a bolt welded to the slave rod - guess someone was trying to increase the clutch travel. You have no idea what other issues this caused.

 

Fascinating thread! Worth the price of my annual subscription alone. I just wish there were pictures to go along with it so I could be sure I was following it correctly. Kudos to all who have contributed!
Glenn

 

The intermediate plate is sprung..but the T adjusters allow it to be "centered" and then float between the two clutch disks. A worn intermediate shaft will cause the clutch disks to not move through the entire range..making for weird engagement issues...and sometimes even binding and not releasing from the pressure plate (or flywheel) etc.

A 928 we are working on is having the exact same prob Hacker is having..except we replaced the intermediate shaft with a brand new one..and still have the same issue. The only difference is that we are using a stage II pressure plate (with extra clamping force)..and that's only making the problem worse. The stock pressure plate and disks will be going back in shortly to see if we can get the double disk to work as advertised...

BTW...the owner of the car uprgraded the clutch setup (since he was having some issues with the clutch to begin with). Those issues were likely caused by a worn intermediate shaft (it was very obvious once compared to a new one...look at the thickness of the splines. They will appear thicker where they are worn down..(likely two areas where the disks ride..separated by a ridge). He did as most people do...and went with one of the upgrade packages..since ..stage 1 is good..so stage II must be better etc....sometimes....staying stock is a nice thing ....that plus the fact that the stock double disk is rated at well above what any stock (and even some boosted apps) are making....

The pic below shows the old vs new intermediate shaft. Not the best pic, but you can see the ridge..

later,
Tom
89GT

 

I was just thinking that - if someone were to read this from top to bottom, they will know more than they ever wanted to about OB clutches.

Tom,
Please let us know ASAP when you have the stock pressure plate installed. I should have a new shaft in my hands tomorrow, installed tomorrow night. If that does not fix the problem - I'll have to order a new IP and be $600 closer to the 928 poor house. If Lorelei finds out about this, I'll be in the dog house.
Sure it's only $600 - after I also bought new wheels, a supercharger, brake pads........I love spring.

 

Austin VeeDub has a used IP on their shelf, unsure what they want, but I thinkI could get it for about $100 or so for you. M.

 

Pictures?

 

Lets see what happens with the new shaft (should be as soon as tomorrow). If that does not work, I'll have to remove parts anyway, might as well try a different IP. $100 is low enough for a gamble.

Thanks!

 

Hacker,

Here is my understanding of the IP operation, which is slightly different than yours.

With no pressure on the clutch pack (ie. clutch released), the IP disc is sprung toward the rear of the car. The IP is captured by the visible "T" portion of the adjusters (when clutch is assembled) and is only allowed to release (toward the rear of the car) by a specific amount. This is one of the primary function of the "T's". If the springs are ok, the IP will release from the flywheel disc until it reaches the stops, which prevent it from releasing too far into the pressure plate-side disc.

When the clutch pedal is lifted and the clutch pack squeezes together, the PP pushes the rear disc into the IP, the IP compresses into the flywheel disc, the flywheel disc is forced into contact with the flywheel.

Now visualize this -- When the IP is adjusted max. toward the rear of the car:

Clutch pedal lifted, PP pushes the rear disc into the IP, the IP springs compress until the IP bottoms on the flywheel side of the "T" adjusters, now the entire IP/spring assemply slides toward the flywheel (recall the "T's" are slotted and this allows the IP spring assembly to shift relative to the aluminum ring which is bolted to the flywheel.). The entire IP/spring assembly continues to move until the entire clutch pack is smashed together. This is the self adjusting part of the clutch. As the friction discs wear the IP/spring assembly will move toward the flywheel to accomodate the wear.

So, regardless if your disc is sticking to the flywheel the IP will only adjust forward as much as geometricaly possible. Loose "T's" may more than likely result in the IP becoming cocked of releasing too far back.

When witnessing the clutch release, the T's should not move, only the IP until stopped by the "T's".

 

Do a search for my adjustment recommendations for this clutch: I posted a thread about 3-4 weeks ago. You do not simply pry the t's up to move it back, you really need to spend another 5 minutes to rotate the clutch around with the pedal pushed in to ensure you can reach up & spin the intermediate shaft (car in neutral) during your adjustment. If the shaft does not free-spin, a disc or two is dragging.

M.

 

(keep adjusting the t's up or down until you have what appears to be equal spacing around themselves, & that the shaft spins freely (the discs will spin freely too as they're splined to the shaft, but the engine/PP/IP will not, at least not by your bare hand

 

I think Scott is right. T should not move during normal clutch operation. Only when pressure plate pushes intermediate ring forward while disks wear out. If those three washers are too weak to keet T from moving symptoms can be similar to clutch shaft bore wear. Only fix for weak spring washers is new intermediate ring. Unless washers are thightened.

Adjusting all the way to the rear method works fine since first release of clutch will force T's to what ever position is correct. Just enough forward to leave all intermediate ring movement range towards the rear. T's need to stay in this one spot until some later clutch release will move it forward to take up slack caused by more worn disks. T's will greep forward at same rate as forward disk wears thinner.

 

What is weird, and I forgot to mention:

If I pump the clutch a few times (5-10) I can usually get the clutch to free up. Sure it goes back again the next time I use it. So whatever is happening "fixes" itself after pumping the clutch over and over and over.........only to "break" the next time I use it.

Does this change things at all?

 

That's exactly what mine did. My throwout bearing is toast. The outside of it looks perfect. Trying to spin it in the car doesn't feel odd, just a little stiff. Upon disassemly of the clutch, I found that it is dragging and grinding inside pretty badly. The getting better as it warmed up symptom is also the same.

PS: I'm not going to say I told you so, but...

 

That is what threw me since the only part of the clutch that would be affected by heat is the fluid in the bearing (or grease on the spline).

Why, did you say this initially?

 

I'm affected by Head quite often.