[Fot] Subject: Re: TR4 Pinion bearing assembly question

[Catpusher at aol.com]

Scott,
 
To add to MJB's and Randall's excellent advise:
 The pinion head bearing supplied by the factory was not off the  shelf 
Timken.
 
The later TR6 pinion depth was adjusted by a selective shim between the  
pinion head and head inner bearing. 
How do you know that the shims that were in the assy were correct?
 
 The pinion drop distance is in the TR2/3 workshop manual, and there  are a 
number of ways to measure it.  I used to go to the factory service  school 
to use their M84A (it was so expensive that the Bay Area dealers would  
borrow it)  I now have that tool and it is VERY Exact. 
 For reliability, and to not turn valuable horsepower into wasted  heat, it 
is important to follow the factory manual.  Use only WD40 to lube  the 
bearings during assy and measuring.  Checking the contact patch is  essential, 
but not as good as proper measurement first.  Watch for anything  that will 
upset the bearings as they are fitted.  Use the correct loctite  on the ring 
gear set screws.
 
This is the short version.
 
TR Regards,
Hardy
 
 
From: "Randall" <TR3driver at ca.rr.com>
To: "''Friends of  Triumph' Triumph'" <fot at autox.team.net>
Subject: Re: [Fot] TR4 Pinion  bearing assembly question

> 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