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MG Midget and Sprite Technical - Oil in Brake Drum

Following an unplanned off-road experience which destroyed a rear wheel, oil has beenleaking into the brake drum.

On removing the brake drum it was obvious that the flange of the half shaft wasn't sitting evenly against the face of the hub. Bearings and oil seal were checked and found to be OK and thinking the half shaft may have been bent, a replacement half-shaft was fitted.

However with the new half-shaft in place, the situation remains the same, with the uneven mating of the hub and half-shaft faces and the continuing oil-leak.

Any suggestions on what has gone wrong here would be appreciated.

Dave
D MATTHEWS

Dave
Have been involved with a similar situation recently. A Sprite hit a kerbstone damaging the rear wheel. The halfshaft was apparently true and the hub seemingly in good order but the two would not run true. As a bodge to give time to find a new axle casing, as the casing was bent, the hub and halfshaft were pulled tight. The bodge caused the end of the half shaft to tear off returning from Spa.


A 'new' back axle casing was found but as often is the case the oil seal bearing face was grooved. Instead of fitting a speedy sleeve a 6207-2RS bearing was fitted negating the need for the oil seal. These bearings 35x72x17 can be had from the likes of SKF with steel or 'rubber' seals either on one or both sides.
Alan
www.masckent.org
Alan Anstead

Alan,

Strictly speaking the bearings with steel "seals" are shields and don't seal, they keep debris out of the bearings but will allow for some transfer of lubricant in/out of the bearing.
David Billington

Maybe I should also clarify it wasnt my car.
Alan
Alan Anstead

Thanks Alan, your explanation fits in with my worst fears that the axle casing may have been bent.

While the half shaft is nipped up tight to the hub on one side, the diametrically opposite side has a gap of approx. eighth of an inch.

Fortunately I have another back axle (but a lower ratio diff.)

Dave
D MATTHEWS

David,

Being the person who rebuilt the rear axle Alan was writing about, I used a double sided sealed bearing with rubber seals, these may leak a small amount of lubricant pass the seals but if the drain hole in the backplate mounting is kept clear any leakage should run down the back of the backplate keeping the brake shoes clean.

I might start a thread on rear bearing end float,there should not be any but of all the gaskets I have used between the half shaft and hub I have always ended up with end float. I now have a small stock of different thickness gasket paper and make my own. On the axle I built the supplied gasket was 0.028" which gave me end float I ended up using paper 0.010" to eliminate endfloat. Anyone else had the same problem?

Mike
M J Pearson

Mike / Dave
My imput was the original bodge to the symptoms you have with the two faces not mating. It was only meant to buy time to locate a new axle casing. It was not meant to survive Spa & back.
When the car was 'pulling the train' on an overtake, eleven miles out from Calais, on the return trip, on the outside of three lanes the end cap of the halfshaft cried "Enough".

Not only did Mike rebuild the back axle replacing the casing he also polished the endcap affixed a Spa Classic decal and presented it as a trophy to the car owner at the last Kent Masc monthly meet.
see www.masckent.org)

The workshop manual for a Frogeye states:-
( Section H4 Hub Assembly )
If, in an emergency, a paper joint washer is hand made, ensure that it is about 0.010 in.(.254mm) thick. An oil leak will invariably result if the washer is too thin.
This, to me, suggests that the gasket is 0.010 and that modern gaskets are made incorrectly - like most things.
Alan
Alan Anstead

Hi Mike,

Yes, I had same problem when rebuilding my rear axle. The first bearing and gasket kit had thick (cereal packet thickness) gaskets and there was loads of end float.

Another supplier sent thin paper gaskets. Still a little end float.

In the end I decided to ditch the gasket all together on the basis that it reduced the float and that it shouldn't leak anyway as loads of other things are sealed with just an O-ring, so the gasket is just another thing to go wrong.

I did write up some notes on this, I thought I posted them in a thread sometime back, but perhaps not.

Cheers,
Malcolm.
M Le Chevalier

My understanding of sealed bearings is that although there may be minimal seepage of lubricant out of the brearing the idea is that the seal is intended to keep all the lubricant in the bearing and the crud out. I would expect it to effectively prevent the rear axle oil passing "through" the bearing and escaping into the big wide world beyond.
THey do not require a separate source of lubrication for life and I have used them in food and other applications where lubricant contamination matters. I used them on my back axle four years ago.
The one downside is that the lip seal doesn't get lubricated as the oil doesn't reach it.
Graeme Williams

Somewhere in the Spridget world, someone mentioned an oversize (.125) o ring that was to seal better. Haven't tried it myself. A hardware store would be a likely source.
J Bubela

This thread was discussed between 02/08/2015 and 04/08/2015

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