Kevin Ritter

I have a 1982 Porsche 928 5 speed. I am in the process of reinstalling the clutch assembly. I want to make sure that the clutch intermediate shaft rests properly in the newly installed pilot bearing. I’ve been told that it’s possible to adjust the clutch intermediate shaft where it is coupled at the torque tube so that the end of the clutch intermediate shaft rides in the pilot bearing properly. I don’t see how this is possible, because there are grooves on both shafts to accept the sides of the 2 bolts in the coupler. Perhaps there’s only some fine adjustment? The reason I ask is that apparently there is a technical service bulletin that indicates that the end of the intermediate shaft will not rest squarely in the middle of the pilot bearing unless it’s adjusted properly.

Michael Benno

I don't see how that is possible. The intermediate shaft is locked into a fixed position relative to the driveshaft via the groves and the clamp. The grooves should not offer any amount of run-out adjustment. Edit: I just scanned through all the TSB's and didn't see any reference to the adjustment (TSB's Link)

Kevin Ritter

Thank you very much for taking the time to respond. it’s most appreciated. I concur with your assessment; thank you for providing the image of the coupler and associated indentations to accept the bolts on each shaft end. By the way, is it possible to search the technical service bulletin by keyword? I am very impressed that you were able to survey the entire 800 page bulletin! Also, thanks for providing the link.

Michael Benno

Yes, the TSBs are in Adobe PDF file format. You can download the PDF and open it using Adobe Acrobat Reader (free), which has powerful search functions. I searched for "clutch," "intermediate," and "shaft." There was a separate search, and I did not see a TSB referring to adjustment.

Mrmerlin

NOTE to set the stub shaft into your pilot bearing do this.
fit the stub shaft and the guide tube into the pilot bearing and bolt the guide tube in.
Then make sure the bell housing is bolted to the block,

NOTE in other instructions i detail to loosen the 4 bell housing bolts to 3 turns from out ,
and remove the 2 trans mount bolts then slide the bell housing/TT and Transaxle back on the bell housing bolts.
If the bell housing isnot bolted to the block then the measurement will be off.

Push the stub shaft into the pilot bearing as far as you can then slide it out about 3 MM
this will put the bearing surface of the stub shaft into the center of the Pilot bearing,
Then take a marker and on the rear side of the guide tube mark the stub shaft so you can see the alignment line.
Once this is done it will be possible for you to figure out how to set the stubshaft depth with the rest of the clutch parts in the way.

Kevin Ritter

Thank you very much for contributing to this ride. So, apparently adjustment is possible. However, I am at a loss with respect to understanding how such adjustment is possible given the indentations on both ends of the shaft designed to accept the side of the bolts threaded into the coupler. As detailed in Michael’s contribution to this thread (see above)

Mrmerlin

Well first you have to realise it’s a precision made machine and the cutouts in the shaft are a little bit bigger than the bolt. So when everything‘s put together there’s a little bit of play either way which can be moved. The first thing to do though is to properly set the stub shaft and then put in your rear pinch bolt
the fit the front clamp

Kevin Ritter

Ah. That makes perfect sense, in fact that was where my intuition was leading me.

Constantine

To add a bit more detail to this discussion, this picture shows the engine end of the 928 5spd drive shaft (top) and transmission end (bottom).

The transmission end has a slightly longer cutout for the pinch bolt to help adjust the drive shaft fore and aft position within the TT assembly. This helps position the front nub of the clutch stub shaft correctly within the pilot bearing using Mr. Merlin's excellent instructions.

Cheers.