[Fot] TR4 Pinion bearing assembly question

Randall TR3driver at ca.rr.com
Sat Nov 9 16:55:56 MST 2013


> Question - why is the outer race shimmed at the housing,

Stronger that way.

> If this is to position the pinion
> correctly fore/aft so that it lands correctly relative to the 
> crown gear, I
> wouldn't think a few thou would make a difference.

It's the shims next to the pinion gear that set the gear position, and a few thou does make a big difference.

>  but with variations between the old and new 
> bearings, I have no
> idea if this will result in the same spacing.

Reassemble the bearings you removed, measure the thickness, compare to the new ones.  Normally they will be exactly the same
thickness (but not always).  I don't have the fancy tools, so I used a Formica countertop as a surface plate, and a digital caliper
with a depth attachment to measure the height through the center of the bearing.  The "Made in India" carrier bearings weren't even
the same as each other, so I pitched them and bought some good Timken that match the old ones exactly (within the accuracy of my
measuring setup).

Chances are that you won't want to reuse the old shims, they almost always get damaged during the removal process.  It doesn't seem
like a crease or two would make a difference, but it does.

After you think it's right, check the contact pattern.

Randall



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