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MG MGA - Half-shaft oil leak

Yet again one of my rear axle half shaft is leaking oil. In the past I've renewed oil seals and paper gaskets but the problem still resurfaces. My car has the earlier hub and half-shaft without the 'O' ring.

My understanding is the oil seal stops most of the oil getting through, while the paper gasket prevents any oil which does getpast from leaking into the brake drum.

Assuming the above is correct should I be using sealant on the gasket to assist in preventing oil leaks?

One of the issues appears to be that there is only one small bolt which fixes the half-shaft to the hub which I presume can pull the surfaces together unevenly. Or is it the brake drum nuts which pull the two surfaces together?

Any suggestions on how to achieve an oil tight seal appreciated.

Regards...John
J Bray

John, the oil seal stops the oil from leaking to outside the drum at the back. The gasket seals from leaks into the drum. The pressure is in fact the brake drum bolts not the retaining screw. I would put some Hermetite or equivalent gasket goo on both sides of the paper, and check the surfaces are flat with no nicks on them.
A Pearse

Thanks for the confirmation, I'll try some sealant after checking everything over....JB
J Bray

Are you sure the oil is getting past the gasket? Make sure that the it is not leaking around the oil seal because it has worn a groove on the axle housing.
Malcolm Asquith

Malcolm,

It is only a very small amount of oil, which is detectable where the half shaft flange meets the hub face.

The problem is that over the course of a year it combines with dust in the drum producing a sticky substance which can cause the handbrake to stick occasionally.

Not a significant problem other than its coming up to the annual MOT

Regards...John
J Bray

Hopefully you won't need to consult Barney's "Speedi-Sleeve" page on http://mgaguru.com/mgtech/rearaxle/ra101.htm. It looks cool, but gluing a paper gasket sounds a lot easier!
Chuck Mosher

Hi John, I had a persistent oil leak from one of my hubs. Check that the mating surfaces of the half shaft and the hub are both free of burrs. Often DPO's will use force to pry the halfshaft out, leaving raised burrs. If you find burrs, carefully file them flat, then re assemble using a new gasket. Filing my burrs, reduced the hub leak, but didnt quite cure it. So I cut a new gasket that I fabricated out of an old car inner tube. the home made rubber gasket cured the leak. Good luck, Glenn
Glenn Hedrich

Hi Glenn,

I'm pleased you were able to respond in what I know are still very difficult times.

When I looked at the gaskets in my local suppliers they do seem to vary in thickness and I had considered making one out of thin cork sheet.

However now I realise why I hadn't thrown the remaining bits of an old inner tube away. Its been used to make various gaskets in the past, I just hadn't thought of it for the half shaft. The sort of simple solution I like with added environmental benefits of re-using redundant parts.

Regards...John

J Bray

Are your inner tubes made from synthetic rubber?
Oil will attack natural rubber.

Mick
M F Anderson

I would be wary of using too thick a gasket, such as rubber inner tube. First, the shaft flange abuts the bearing outer race, preventing its moving out of place, so you may not be clamping the bearing tightly. Second, a thick compressible gasket could allow distortion of the flange if it were unevenly tightened. Maybe I'm being a bit particular though.
Art
A Pearse

Mick, my inner tubes are old MGA ones at least 35 years old. So probably not synthetic, although I suspect the ones currently on the car probably are.

Art the rubber is not to thick, and the secret is to use the bits without any seams in.

Thank you both for your concerns, and good advice.

Regards...John
J Bray

Hi Mick. Im sure the old inner tube that I used was NOT synthetic, but natural rubber. It was quite thin, and sealed nicely without using any gasket goo. When I needed to pull the halfshaft about 10 years later, to change a bearing, the gasket fell apart, when I tried to remove it, verifying your note about rubber deterioration. However, the gasket was not leaking prior to it's removal, and did last about 10 years. Since the gasket is pretty easy to make and replace, and the material cost is free, this seems like a viable solution to a persistent leak. Cheers, Glenn
Glenn Hedrich



Hi John. Is your car a wire wheel or disc wheel?
I've known cars with wire wheels to leak oil from the axle cap inside the hub, the pressure fit of the expandable cap could be miss-aligned and allow a small amount of oil to find its way into the works.
Even though it has to overcome the passage around the 'Knock off' If this is so, a small amount of sealant rubbed in around the joint will fix the problem. Oil has a funny way of getting through all kinds of seals, threads etc., and working its way to where you don't want it.
Regars, Rod
R.A. Gregg

This thread was discussed between 29/09/2008 and 02/10/2008

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