It also stops the inner races turning on the stub-axle and wrecking it -
except possibly under catastrophic siezure of the bearing, no doubt due to
omitting the shims and using pre-load ...
----- Original Message -----
From: Glenn Schnittke <schnittke@mindspring.com>
To: <mgs@autox.team.net>
Sent: Friday, November 10, 2000 3:37 PM
Subject: Still more on wheel bearings
> There's been a lot of certainty here about having to rebuild the front
> wheel bearing package the way it was originally designed, but nothing
about
> WHY.
>
> All MGB's (and I believe the A's and the later T series) were designed
with
> tapered roller bearings, a cup spacer and shims. If you were to look in
> your Bently manual on page 232 you will see a cross-section of the unit
> (fig. K.1). You will see that surrounding the stub axle itself, starting
> from the kingpin end are; the oil seal, the inner bearing, the cup spacer,
> the shims, the outer bearing, the retaining washer and then the hub nut.
> This combination, with the inner races of the bearings trapped between the
> oil seal, cup spacer, shims, and retaining washer, effectively build a
> second and larger diameter inner cylinder around the stub axle using the
> axle as a stabilizing inner core. In order for the outer bearing to be
> placed at the proper position for the correct preload, shims of different
> sizes must be inserted between the outer bearing and the cup spacer. Then
> the hub nut is installed at a huge torque and the entire unit is bound
> together.
>
> What this effectively does is to increase the diameter of the stub axle
> making it that much stronger. You CAN build the bearings into place
without
> these pieces, but the real danger involved in not using the spacer and
> shims is that you will be driving around on a set of front stub axles that
> aren't as strong as the engineers had intended for the forces ivolved. The
> probability of bending or even breaking an axle when encountering a
pothole
> at speed multiplies exponentially.
>
> I don't have the numbers, not being a professional engineer myself, but at
> the possible cost of an entire stub axle replacement or the loss of life,
> limb, etc., my recommendation is to suffer through the extra beer drinking
> time it will take to build it correctly. The most THAT will cost is an
> extra six-pack and maybe a visit to the chiropractor.
>
> Now, are there any questions?
>
> Glenn
> -----------------------------------------
> Glenn Schnittke
> schnittke@mindspring.com
> Home: 615-385-2800
> ---------------------------------------------
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