[Healeys] Spun bearing and gasket issue - summary

[Steve Gerow]

[Xposted on the Forum]

If you've had a spun rear wheel bearing and/or leaking seal, this may be of
interest.

 

Recently one of my rear wheel bearing seals started to leak. Ordering a new
seal from Tom's Import Toys, Tom Monaco mentioned the leakage was caused by
heat from the bearing spinning in the housing, and that he'd replaced about
a hundred rear wheel bearings to fix this problem. The cure was to install a
new bearing using a combination of heat and cold to shrink-fit the bearing
into the hub and onto the axle. I'm guessing the hub housing has some wear
if the bearing's been spinning.

 

According to the Manual, Section J, the bearing spacer must protrude .001" -
.004" beyond the paper gasket. This allows the lug nuts to tightly
metal-to-metal grip the outer ring of the bearing in the hub. The inner ring
is tightly gripped by the center octagon nut. (Thanks to Gary Hodson for
pointing this passage out.)

 

In my opinion, the spun bearing problem is caused by excess thickness of the
replacement gaskets, which prevents positive gripping of the bearing outer
ring, as called for by the manual.

I measured my non-gasket clearance at .004". This can vary as the thickness
of the bearings can vary by a few thousandths (.900" and .905" on two old
bearings I have).

 

The Moss replacement gasket is .015" thick and compresses down to
approximately .011" - therefore the bearing outer ring is not gripped at all
and the hub depends on the shrink fit of the bearing only.

In my opinion, the solution is to make your own gasket from paper such that
the thickness is .001" less than the protrusion as measured above. Legal pad
paper is .003"; copier paper is .004";  9x12 envelope paper is .005".

If your car doesn't have the o-ring, or you don't have a micrometer, you
could leave the gasket off and use a thin bead of gasket goop, such as Right
Stuff or Form-a-Gasket to effect the oil seal.

 

Axle flange note: The outer edge of the axle flange is not distorted by
being unsupported by the gasket. Because of the thickness of the brake drum
and splined hub flange, in combination with the strength of the hub itself,
the flange will not distort by tightening the lug nuts.

 

Would be curious to measure an original gasket from back in the day.

 

Documentation: 

http://www.pbase.com/stevegerow/healey_rear_bearing

 

--

 

Steve Gerow

Altadena, CA, USA

BN6

Check out my galleries:

http://www.pbase.com/stevegerow/

 

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