MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Keeping the diff oil in...

How do you racing types and other track day people keep the oil in?

Mine all came out at Croft and now my diff is toast.

Got some lovely new seals (lots nicer than other offerings, thanks Malcolm) and they work now, but will they work on track?

The ones that were in were brand new (although not as nice as my new ones).

I reckon it's coming out for 2 reasons, one is hub flex making a gap in the seal, and the other is that all of the oil is in one end of the axle...

Anyone baffled the rear axle? or is there enough oil in there to keep the diff under oil when it's all in one end?

Rob Armstrong

I've never had a problem with the diff oil.

If your hub is flexing that much, you probably have a sloppy bearing - also likely to snap the end off your halfshaft.
Dave O'Neill 2

Rob,

I had exactly the same problem after the restoration of our 1380 Minor (same rear hub arrangement), and a track day on the Imola GP circuit. Both hubs leaking oil badly.

Swapped to Peter May's double bearing hubs and ~50,000 miles and many track days later and no problems. Not a cheap fix, but very satisfactory.

Richard
Richard Wale

Thanks Rob, glad you like the kit.

Did you crank some nuts up tight on the studs before doing up the retaining screw? This i think helps a lot. Its easier if the car is in gear when you do, to stop things spinning.

Sure it is coming out the hub/shaft interface? Or is it coming out the rear oil seal?

How was the bearing fit in the hub? It should be a good and tight press fit.

Cheers
Malcolm
Malcolm Le Chevalier

Is the axle casing oil breather clear?
Guyw

IIRC the axle casing is baffled (a bit) as standard.
Attention to detail on fit and assembly of hub bearings, oil seal, O ring and gasket are all important, and don't forget that having an effective breather is essential too. On mine it's the pinion seal that usually leaks!
David Smith

Having done many track days, autotests, and hillclimbs and never had an oil leak from the rear axle I would presume something is amiss in the assembly allowing it to leak. With the standard axle design the halfshaft takes the main bending load created by cornering with the bearing taking the side and vertical loads. IIRC have a look at semi-floating vs fully floating axle design. The double bearing hub takes bending load off the halfshaft and transfers it to the axle casing.
David Billington

Ran an Anglia housing in mine and never had a leak problem BUT
With track days, our local track is mostly lh turns and driving hard, as you do all the oil goes up the rh tube and starves the pinion etc of lube
I had to fit baffles in the pumpkin end of the diff tubes ,extended the diff breather with a hose up through the boot floor to the top of the rear firewall, and overfilled the diff an extra 1/2-3/4 litre by jacking the lh side of the car up and making sure the rh side tube was filling up a bit while filling the housing - solved the blue teeth problem
willy
William Revit

We had our LH seal leak, but not the RH. Couldn't see anything wrong, all was tight, seal surface mint, etc. In the end we tried sealed a bearing and that stopped it.
Despite sticky tyres and long loopy corners we haven't had usfficent surge away from the centre to damage the diff. Maybe we are just chicken :-)
Paul Walbran

Thanks all. It's the rubber seal that's leaked, the half shaft paper gasket is fine.

The bearing was new (but a cheap Chinese one) and is now also dead, play and rumble. Got one of Malcolms Eu ones in and have to say the quality and fit is a lot better, see if it survives ;)

Breathing is fine, I can hear it hiss when I let the diff oil out.

I'll have a look at sealed bearings, then possibly the double hub, but it is quite expensive...

As a reminder, it's this sort of thing that has caused the leak..

http://www.flickr.com/#/photos/34910348@N08/27474689144/in/set-72157639738071493/
Rob Armstrong

As David S said, the axle is already baffled. (photo)

Dave O'Neill 2

I've always found the issue is the half shaft gasket thickness. Another thumbs up for Malcolm's kit - swopped to a LSD at Mallory recently and not a drop of oil lost after replacing both sides with a thinner gasket from the kit.
John Collinson

Glad you liked it too John.

It's mostly just a bit of fun and something to do whilst I am an unemployed bum. But as unemploydom continues I might develop a few more ideas I have.

Please like the Facebook page: http://www.facebook.com/chevalierclassics/

There is some more info on the kits there too.

Cheers,
Malcolm
Malcolm Le Chevalier

Incidently, whilst talking of half shaft bearing seals, for the tight fisted brigade, the discarded rubber seal makes a useful replacement for fitting between the rev counter or speedometer and the dashboard. It has to stretch a little but fits quite nicely.

Rob, being from Yorkshire, probably already knows this!
Guyw

Rob
I've never had a problem you report with loosing diff oil despite a number of spirited track days (admittedly I've not got the power and torque of a K-series). I have had a leak from the near side hub for some time (never enough to lose the oil but enough to contaminate the brake shoes). Fed up with replacing the brake shoes before every MoT I had the hub off last year and fitted one of these:

6207 2RS1 SKF Deep Groove Bearing - 35 x 72 x 17mm

It is completely sealed for life (rubber seals), fitted perfectly and so far no problems despite some more track days.

Great videos as well.
Chris Hasluck

I've read lots of stuff about the sealed bearings being a good thing. certainly a cheaper alternative to the double hubs.

I guess I need to inspect the axle casing for wear on the seal lands as well, otherwise I'm not going to get anywhere...

The diff is replaced, much much better, the old one had eaten through the hardened teeth into the soft metal underneath on the crown wheel. and the LHS half shaft (the outer one at Croft) has been bending so much it's spoilt the diff output bearing surround, serious trace marks on the shaft just upstream of the splines. Must have been like a banana in there. Surprised it didn't snap the end off. Both powertune bearings (not Malcolms ones) are toast, one with huge play (the LHS one) and one with rumble death. Not bad for 23 miles use.

Guy, the left over O rings also work for other stuff like holding bike mudguards on :)
Rob Armstrong

Interested in this as I also have leaky hubs but I don't track, and I'm sure I don't drive it that hard!

I think when I get round to it, Malc will get a call (just 'liked' you on Facebook) but not sure whether to go for sealed bearings and have done with it...
Karl Bielby

This thread was discussed between 15/07/2016 and 18/07/2016

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now