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MG MGB Technical - Axle oil leaks at hubs

Hi All,

Had my 72 B for nearly 20 years but this last year been having issues with the rear axle leaking oil through the hubs (tell tale streaks of oil on my wheels).

I replaced the LH seal about a year ago, then soon after the RH seal started leaking so replaced that as well. Now the LH is leaking again and the RH is still weeping slightly. In both cases I cleaned the marks on the collar that the seal runs on.

Am I missing something? Should there be any sealant under the collar? Is it just poor quality seals?

I thought about a blocked breather, and my parts book shows a breather on the Banjo axle but not on the tube axle that I have?

Any tips appreciated.
Thanks,
Glenn.
G Britnell

The tube axle does have a breather, although Moss refer to it as a valve!

Item no 18 on this page...

http://www.moss-europe.co.uk/shop-by-model/mg/mgb-c-v8/clutch-gearbox-axle/axles-differentials/rear-axle-tube-type.html

It looks like it is fitted to the RH tube, just outboard of the diff.
Dave O'Neill 2

Nice one thanks. That is not on the old parts book I was using. Bought a new one as I bet my old one breaks when I try to remove it.
G Britnell

Make sure the collars are not grooved or scratched. There is no sealant, when the hub nut is fully tight the collar and bearing inner race are clamped tightly between the hub and the flange on the half-shaft, so there should be no opportunity for leaks - unless any of those surfaces are damaged or dirty.

The bearing cap should clamp the outer race into the axle casing, so again there shouldn't be opportunity for leaks from that area, again subject to surfaces being sound and clean.

Determine whether it is oil from the lip of the seal or elsewhere, or maybe even hydraulic fluid. These leaks should run down the backplate and/or brake drum (contaminating the shoes) and drop onto the in-board part of the wheel rim. Over-greasing wire-wheel splines causes dirty marks up the spokes.
paulh4

When I replace the outer bearing retainer, after bearing or seal replacement, apart from cleaning and demurring the mating surfaces I always smear the surfaces with Hylomar, as there is an opportunity for leaks from that area.!
Allan Reeling

Cheers guys. My car is on bolt on minilites and fortunately the oil is coming out behind the centre cap and running along the outer wheel face. The brakes are dry, the oil is not getting into the drums and the cylinders are not leaking. I'd be even more fed up if this had cost me 2 sets of shoes!
G Britnell

That seems to be coming from inside the hub then, i.e. from between the half-shaft, spacer, collar, hub nut and washer. Try some sealant round the half-shaft, spacer, and inside the collar.
paulh4

I had a similar problem with my mg. The near side kept leaking oil even after fiting new oil seals twice making the car fail the mot. I fitted a new cone that the oil seal runs on even though no wear could be seen on it,it cured it. Also make sure you have not over filled the diff.
Trevor Harvey

This thread was discussed between 14/06/2017 and 16/06/2017

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