Clutch Release Upgrade

[Jon B]

As I recently upgraded a clutch fork pivot on a 1970 911S, I thought I'd photograph the pieces to illustrate the differences. This upgrade applies to all 1970 and 1971 911 models.

The clutch fork pivot is a ballpin fastened inside the transmission bellhousing. Original ballpins had nylon bushings, held in place by a 6mm locking nut. As these nuts, threaded posts and bushings began to fail, Porsche re-designed the pin to eliminate the separate pieces. Original ballpins should be replaced whenever possible, regardless of condition. A different base washer and leaf spring must also be used.

Ballpin....................911.116.772.11
Base Washer...........911.116.743.01
Leaf Spring..............911.116.774.01

Photos below show original pieces on left, updated pieces on right...







Jon B.
Vista, CA

[dho]

Resurrecting an old thread-if the flywheel has been surfaced, is it necessary or advisable to insert a shim between the bell housing and leaf spring to compensate for the material removed from the flywheel? If yes, and the amount of material removed is unknown, what would be the recommended shim thickness, 0.5mm?

Thanks for the comments.

dho

[ajwans]

JimmyT makes an upgraded part for this: https://www.early911sregistry.org/fo...911-116-772-11

- Andrew

[dho]

Thanks, Andrew. I have Jimmy’s bolt on the way. He is the one who suggested the shim, but I have not seen that referenced anywhere else; accordingly, I’m wondering what the collective wisdom is.

dho

[edmayo]

Yes, the shim is normal practice for turned flywheels. After engine and trans is bolted in but before any other hook-ups do your clutch cable attachment and adjustment and operate pedal watching that clutch fork doesn't hit anything.

[dho]

Got it. Thank you, Ed.

dho

[Jon B]

Yes, it's advisable to shim the ballpin if the flywheel has been resurfaced, ideally by the same amount.
This applies to the earlier 901 and 914 ballpins as well.

But also note that the 1-piece factory ballpin is not a direct replacement for the original piece; it requires a thicker base washer for the proper installed dimension.
Compare the effective installed lengths of the two versions in my first picture.

I don't know how Jimmy T made his version, but I suspect it's a replica of the factory 1-piece version.
If so, it will also require a much thicker base washer, a washer stack or a spacer.

Jon B.
Vista, CA

[dho]

Yes, Jon, Jimmy T's version requires the upgraded spring, cone washer, and when the flywheel has been surfaced, the shim.

dho