Rear wheel bearing woes

[Jesse]

I recently removed a SKF rear wheel bearing from a steel trailing arm (-71), no rust and no damage in the "cage"

When installing a new FAG bearing I discovered that the bearing initially had some resistance but once it came half an inch in it just fell in place and I am able to move it in/out with my bare hands. So... I measured the SKF bearing that had been in... Same size as the FAG..

Is it possible to use Loctite 660 or similar products to bond the outer race to the trailing arm? I have several trailing arms but keen on finding a way to save this one.

Regards
Jesse

[911hillclimber]

I think a call to their tech dept tomorrow will give you the answer

[inaglasshouse]

Leaving aside the question of why the old bearing held securely but the identical replacement doesn't... here are some things I know:

1) the hole for the bearing in steel trailing arms did used to wear / deform
2) Because of 1, Porsche offered an oversize bearing for repair purposes. Don't know if they still do, but imagine the usual bearing manufacturers you mention would have something.
3) Some UK specialists recommend the oversize bearing approach. Machine out the arm to an interference fit. But there's not much material to work with...
4) At least one UK specialist says, within reason, it's fine to use Loctite 660 (or similar - needs to have gap filling properties). They have done so on race and road cars, not had a failure yet.

How cold is it in Sweden? Has your bearing shrunk ?

Cheers, Richard.

[fetuhoe]

This problem is relatively common and it is concerned with the removal of the old bearing which tends to deform the housing when the bearing is pressed out at a slight angle.

The Oversized bearing is NLA and they used to cost over £200 + VAT each.

We have just ordered some Koyo bearings which are 75.05mm OD instead of 75mm - The old Oversize Porsche Bearing was around 75.25mm so they won't help too much.

When the housing has deformed the result is an annoying 'click' during rapid changes of direction.

The common explanation is that the bearing is sliding in the housing but as it is located with a retaining plate the bearing just 'rocks' in the small clearance.

The 'click' tends to be consistent and can persist for years without much change.

If you use a Loctite Retainer you would be better off using 660 which has a gap filling capability and we have used this successfully in the past.

None of the bearing manufacturers offers any oversized bearings and machining out the housing will reduce the it's strength and possibly make matter worse. Making a custom batch of bearings would be unaffordable in real terms.

There is a bearing at 76mm OD but it is 38mm wide rather than 37mm.

It is possible to centreless grind the outer race to 75.3 but it would also need a custom retainer to deal with the extra width.


I would try the 660 as a first move.