Alfa Romeo Bulletin Board & Forums - View Single Post - noises following pinion seal replacement
View Single Post
post #6 of (permalink) Old 08-08-2011, 06:27 AM
Trained (ex)Professional

1953-2018 RIP

Platinum SubscriberAdministrator
papajam's Avatar
Join Date: Feb 2003
Location: New Jersey USA
Posts: 16,232
Originally Posted by Alfajay View Post
The thing that jumped out at me in your description was "I ... tightened the pinion nut good and tight with a 1/2" socket".
That jumped out at me too.

Pinion bearing pre-load is adjusted with shims, not pinion nut torque or a crush collar. If the pre-load is correct, the torque on the nut will not change the pre-load. What happens over time as the bearings and races wear, the torque on the nut gradually gets less and less. If one now retorques the nut, or tightens it good and tight, the bearing pre-load can be so high as to prevent the pinion from even spinning!
The trick to replacing the pinion seal is to first note the torque on the nut before removing the nut. After seal replacement, torque the nut to the previous value (disregarding the torque spec in the book).

I'd wager the noise is excessive pinion bearing pre-load. To remedy this, remove the driveshaft and loosen the nut. Then tighten the nut by hand until there is zero horizontal, vertical and axial play in the pinion. Now note the resistance required to turn the pinion. Gradually tighten the nut until the resistance starts to increase and stop there. Then lock down the nut.


Series 2 USA 1750 GTV (in Series 1 European clothing)
papajam is offline  
For the best viewing experience please update your browser to Google Chrome