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MG MGA - Banjo axle oil problem

I am running a banjo axle in a race car, and blowing large amounts of oil out of the breather.
Anyone come across this before?
It does have a plate type LSD


Colin Parkinson

Art Pearse

Thanks Art!! How do you overfill, when it drips out of the level plug!!

Colin Parkinson

OK, guess not!
Art Pearse

Been thinking about this one Colin (trying to get out of the box). After checking my car, and seeing very little in the way of oil up there, I came up with the following:

Does the breather tube have the cap fitted? or could it be damaged?
Could the axle casing be damaged in that area?
Could the oil be foaming? or otherwise be an unsuitable type? maybe even incorrectly identified on the container?
Could it be anything to do with the proximity of the exhaust causing excess temperatures?

When you say large amounts, is it blowing enough oil out to drip or just to be annoying

Maybe you are just driving too fast!!! LOL

Neil McGurk

I recall that some Mustangs had a differential problem when the cars were racing at very high speeds. Seems that under these speeds the oil was being slung away form the gears. The differentials were not designed for these speeds! Have a good day!

John Progess

Neil thanks for your thoughts. In order : the breather is a new, short plastic type the same as the old brass one. Axle casing is perfect. Oil foaming? It is a Millers competition oil I think 80/90 for plate type LSD. Exhaust plenty of clearance, and not that hot.
When I say blowing, it is going back onto the fuel tank, and then running off!
We are talking about a problem here, not an inconvenience!!
What I have done today, is an old trick of mine. A different fitting into the hole, then a flexible pipe going up and round in a circle, with the outlet below the axle.
Not tried it yet, but at least if it blows, it goes on the floor, not on top of the tank.

Thanks for your help, and if anyone else has any other thoughts, I will happily consider them.

Colin Parkinson


I presume you have confirmed it is coming out of the breather and not the front oil seal leaking, resulting in the oil being flung out by the rotation of the u/j flange?

Just a thought.
Steve Gyles

Did you read my response on the MGB board?
Can make more specific recommendations re breather construction.

FR Millmore

Steve, yes, diff case is as clean as a whistle.

FRM, will read now!

Colin Parkinson

Simple first:
One of my favorites for such problems is a sintered bronze filter on a pipe fitting, commonly sold as pneumatic control valve muffler/filter. I use them as fuel filters, fuel tank vent/flame arrestors, etc. (keeps mudwasps & spiders out of your fuel tank vents!! = dead Rover on the road at night due to mudwasp in vent pipe under/inside rear wing)

Like so, Part# 293101

Keeps dirt & water out. Cheap, durable, easy to find from industrial pneumatic suppliers.

I frequently thread the ID and screw in an extension tube. In your axle, such a tube, say 1" long with a 1/16 center bore, would prevent the oil from easily getting into the fitting; the existing config acts as a funnel. NOT long enough to hit the halfshaft, and use locktite or silver braze the (brass or copper) tube into the fitting. Try it in the OE location before you get crazy.

Otherwise, locate it to the extreme left of the high part of the banjo, out of the oil throw-off (which is upward at the rear of the case) from the CW. The extension tube in this case should be cross drilled and the end blocked, assuming vertical installation. Other than drilling & threading to suit, not bad. If that doesn't work, a bigger one with a more sophisticated baffled extension at the same location.

FR Millmore

FRM, ooh err!! THat's a different take! Must give it some thought

Colin Parkinson

This thread was discussed between 14/07/2009 and 16/07/2009

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