Jherriott

Hey all,

Thanks to our 6 month winter "pause" up here in Canada, I have a 1988 Carrera Coupe with a G50 apart at the moment to do a top end refresh and replace bad valve guides.

While the motor was dropped I took the opportunity to check the clutch and transmission. The clutch had been making an occasional noise only at the moment when the clutch made contact with the flywheel. Therefore no noise when clutch was fully engaged or when fully released.

It turns out the pilot bearing had completely seized and the shaft was rotating within the bearing, wearing down the tip of the input shaft in the process. Unfortunately it looks like even though the clutch and flywheel had been upgraded to the 930 style by the PO, the bearing had not been changed? Unfortunate.

The end of the pilot shaft is now coarse and copper colored. When the new bearing is placed on the end, there is some minute play which causes me to worry. My fear being that the shaft will now want to rotate within the center ring of the bearing.

Questions:

1. Not being completely familiar with the stresses in this example, am I right to worry? Or will the new pilot bearing work fine on the worn shaft?

2. Does this occur frequently enough that there is some fix? Either a resurfacing and treating of the shaft, or a different bearing?

Any suggestions are welcome other than my mechanics suggestion of a new input shaft at a cost of $2,500 just for the part alone. Many Thanks!

r911

mic it and compare with the spec.

Jherriott

kk. I'll check that. But I figure it's out as I can feel the difference when I put the bearing on. So, that being said... according to this ruler's far right measurement it's one-half blonde c-hair...

I'll check tomorrow with the proper mic.

theiceman

one half blonde should be fine . I think Brunette would put you out of tolerance.

Jherriott

So, the mic measure at the unworn tip of the shaft is 14.91mm. The mic measure at the worn part is 14.88mm, making it out by 0.03mm.

I told the guy to make her smooth and grease her up.

Thanks for all your input!

Jase.

Techno Duck

Just a note, i have seen press on sleeves used for worn input shaft tips. I am not sure if the input shaft is machined down to accept the sleeve or if they spec a larger ID pilot bearing though.

Amber Gramps

So you asked another man to polish your shaft?

Jherriott

Haha!

Amber Gramps

When my wife and I were young apartment dwellers my wife noticed the young guy next door had a saltwater aquarium just inside his front door. One day when his door was open she blurted out " hey, I like your wrasse".

Jherriott

When I was younger, I lived next to a guy who was a road paver. He had an unbelievably gorgeous daughter... and she sure did like her asphalt.

Oh boy.