Was getting the 951 tuned on a dyno last night and during the 11th run the clutch went. The pedal is stiff as can be and you can't depress it.

I was almost there! We had just finished 15 PSI tuning and was going to 18 PSI.....but I digress.

Okay.....277 HP and 288 ft-lbs of torque at the wheels on 15 PSI! And it runs sweet!

Had it towed and it's at my house, looked at the inspection window this morning and I see the slave "push pin" that acts on the clutch fork is hitting the window and no longer engaged in the clutch fork. That's why the pedal is stiff as can be, the "push pin" is hard up against a piece of metal.

The slave cylinder looks new, but I don't know this for sure. The clutch is brand new. Here is a picture from one of Raj's clutch replacement procedure for the 968 (awfully helpful as there is no 3" exhaust in the way):

https://rennlist.com/forums/968-foru...acement-2.html



Here is a picture of my 968, I can see that the slave push pin is engaged in the forks:



On the 951, it is literally at left side of the inspection window, about 9 o'clock hard up against the metal circle.

Before I go buy any parts, I would like to figure out what is wrong. Unfortunately, I have a 3" exhaust from the turbo in my way!!!

I was thinking of just backing the slave cylinder mounting bolts back a little and see what I can do with the push pin. Is there a chance it will re-engage? The clutch pedal is all the way up. I had no issues with the clutch in the past few weeks.

Any other advice?

 

if you can reach it, crack open the slave cylinder bleeder screw and then you might be able to compress the "pin" back into the cyl enough to line it up with the fork again...youll lose a bit of fluid though.

 

Okay....it's not the clutch slave cylinder. Dropped the starter and it's whatever the clutch fork pushes on....it no longer pushes on. I can cycle the clutch fork back and forth, the clutch springs are no longer pushing on it......will have to figure out what to do...

 

So I found a good thread on clutch replacement: https://rennlist.com/forums/944-turb...ctorial-2.html

My clutch was just replaced on the car less than 500 miles ago with a new lightened flywheel, 930 pressure plate and clutch, including throw out bearing.

I am having trouble figuring out how the throw out bearing is mounted. Here is a picture from the thread with the pressure plate installed:



Now the pressure plate and throwout bearing installed.....how does the throwout bearing stay in place?



Here is a picture of a throwout bearing from ebay....what are all the circlips and clips for? Is there a failure mechanism that has caused the bearing to no longer work on the pressure plate fingers? I just am having a hard time digesting it right now.

It appears the clutch fork is pushed forward by the slave cylinder, and then pulls the fork at the throwout bearing towards the rear of the car....is that correct?




Here is the bell housing/clutch fork assembly:



I'm wondering if I remove the pin from the clutch fork assembly and try to re-engage it, if that will do anything for me. I really can't figure out. Should I try taking the clutch fork pin out and see if I can re-engage it?

 

Could be a broken clutch fork. Seems fairly common. Depending on the failure, you may not be able to tell without dis-assembly.

 

Wow, we posted at the same time about the fork...

 

Those series of rings are what hold the throwout bearing to the PP.

And +2 to the broken fork theory.

 

I'm thinking it's either a broken fork or somehow the snap ring on the throwout bearing came undone.

Can the fork be removed/replaced without removal of the bell housing? I'm guessing it cannot.

*hit.

 

Nope, gotta take the bellhousing out. Not enough room to squeeze the fork out between the inside back wall of the housing and the PP.

Is that a KEP plate? I think they have a reputation for killing clutch forks.

 

Those pictures are not mine, just linked from the previous post.

I was underneath the car, and the way the fork moves back/forth so easily, and that nothing is rattling with the car running, I would not be surprised if the snap ring is out of place.

Guess I'm going to figure out how to do this in my garage! I've done some research, doesn't look too bad. Good thing is the exhaust is basically brand new with all new hardware. That should be easy to remove. Lots of other stuff on the car is brand new/brand new hardware.

 

The throwout bearing is pretty heavy. If the snap ring popped, then you'd still feel the bearing moving back and forth when you moved the end of the fork. There would be a little bit of effort there. If it's really easy, then the more likely issue is that the fork broke.

My memory is fuzzy, I've only done a clutch once on these cars and it was a few years ago - but I recall having to compress something with a great amount of force to be able to get the lock ring in/out. I don't think it's something that would just fall out on its own.

 

Thanks for the info everyone.

I pulled the fork pin out....and have since put it back in, it's like the end of the fork is heavily worn or something, I can get the fork to sit where it should be and have resistance, but when I push on it a certain way, I can get it to disengage......back to the garage for me to see what I can do.

 

This is a 951, not a 968? On the 951, you'd need to remove the bellhousing to remove the fork. But maybe you could try removing the starter and seeing if there is any "evidence" sitting at the bottom of the bellhousing which could tell you what has happened. I.e., pieces of the clutch fork, pieces of the TOB, etc.

 

This a 951....have to update my picture, have one of each. Trying to find a used fork and having it towed to my friend's house who has a lift and hopefully will change it out this weekend.

 

Had the car towed over to my friend's house....put it up on the lift (which was no easy task due to the configuration of the under carriage) and will be working on it tomorrow/this weekend. Have a new clutch fork (well used....) from DC Automotive.

Hopefully this won't be a total challenge. Already did some of the job, everything from the top except removal of the bell housing grounds. Couldn't see them.....hopefully I don't have to move the bell housing much, maybe I can get away without doing it.

Wish me luck! Read the procedure many times and looked at everything under the car in my garage, seems pretty straight forward.