type 4 clutch not releasing Options

[bangoos]

Hello fellow Porschephiles!

Installed a new clutch disk between two used but in good cond surfaces.
The flywheel surface appears near new and measures new according to specs in the Porsche "Technical Specifications" book that I have. The pressure plate surface also appears near new and is the type 215 Sachs. The disk is also Sachs and measures 10mm thickness. Pilot bearing is clean and well lubed. Input shaft is straight and true. There is no oil or grease on any of the surfaces inside the bell housing, on the back of the engine, or on any of the clutch parts. Side shift trans has new lube with all new seals. All shift rods and junctions are in excellent cond. Using Rennshift shifter. Trans shifted fine before switching to new disc.

Installed new clutch cable. Pedal bushings are good. Cable pulley is good. Cable adjusts well enough.
BUT!
clutch will not fully disengage, therefor no shifting can be done.

I removed the trans yesterday and swapped out the pressure plate while inspecting all surfaces and checking to make sure the pilot was not being jammed some way. Put it all back together, still cannot shift, clutch will not fully disengage; and with a better pressure plate installed this time, the shifting is even more difficult, as the plate is a bit better than the first one. Adjusting the cable to full tight has no effect. Setting it to 1" pedal play works the same as fully tightened cable, no pedal play. Stepping on the pedal makes the clutch slip, but does not fully disengage, no mater how the cable is adjusted.

Mega frustrating.
Is the disc too thick?, The clutch worked and shifted with the used disc in it. Old disc was about 9mm thick, thinner due to age ware. The new Sachs disc measures 10mm. I also have a rebuilt Sachs disc that measures 9.8mm, and several used discs measuring between 8.5 to 9.5mm.

OR?
Is the pressure plate faulty in some way.

Once again, the critical dimensions of the flywheel are correct for use with these parts. Of the above two possible faulty components, the pressure plate seems to me to be the culprit.
How can a pressure plate be faulty?
Warped surface
Scored surface from clamping onto the exposed rivets
faulty diaphragm spring, not levering the plate away from the disc far enough

Seems to me the only possible problem could be the last of the above three potential
problems. The second of which does not exist.

So it is really that I need a new pressure plate?
Can the diaphragm spring be wore out? bent around it's fulcrum ring? Incapable of levering the plate to free the disc?

Your comments are welcome.
Thank you!

[JoeSharp]

There is a pivot in side the bell housing that is adjustable by shiming it in or out. You maybe able to get more adjustment there.

[MikeInMunich]

There is a pivot in side the bell housing that is adjustable by shining it in or out. You maybe able to get more adjustment there.

Thanks for the suggestion Joe. Any other ideas? This is so strange!

Mike

[bangoos]

This is likely the problem. I believe Mike may have mentioned this to me yesterday when we were discussing it. Phone signal here is usually not so good, and I may have mis interpreted what he said, so it did not hit me as relevant, what it very relevant.

I will be out there in a few checking the distance the fork arm is from the port it passed through on it's back side. Probably hitting it now.

Thanks All!

There is a pivot in side the bell housing that is adjustable by shining it in or out. You maybe able to get more adjustment there.

Thanks for the suggestion Joe. Any other ideas? This is so strange!

Mike

[bangoos]

The trans came out in about 45min. The ball pivot point was machined deeply into the mag case. This was the problem. The ball was screwed in so deep, it was necessary to chisel material from around it so I could get a socket on the unusually short hex portion of the part. After doing so, removing the ball revealed a seemingly "too short" portion of thread. The shortness of it meant I could only add a short stack of washers to get me near where I needed to be.

The fork extends beyond the pivot point 2". The arm extension of the fork extends out to the cable about 7" from the pivot point. Adding 3mm shim (two 1.5mm washers added) meant I would pick up about 10.5mm extra travel over the way it had been.

This turned out be be sufficient, but not necessarily optimal. The trans shifts fine now; the clutch fully disengages in the normal manner.

Once I had removed and reinstalled it once, the second time around took less than 1/2 the time it took the first time. Having a trans jack makes a big difference. It took more time to figure out what to do about the deeply seated pivot ball, than it did to remove the trans. Putting the trans back in is more strenuous; it likes to be perfectly aligned before slipping back into place.

Job accomplished, now for the dead newly rebuilt alternator.

Thank you all!

This is likely the problem. I believe Mike may have mentioned this to me yesterday when we were discussing it. Phone signal here is usually not so good, and I may have mis interpreted what he said, so it did not hit me as relevant, what it very relevant.

I will be out there in a few checking the distance the fork arm is from the port it passed through on it's back side. Probably hitting it now.

Thanks All!

There is a pivot in side the bell housing that is adjustable by shining it in or out. You maybe able to get more adjustment there.

Thanks for the suggestion Joe. Any other ideas? This is so strange!

Mike