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MG MGB Technical - Another Leaking OD

I have a later LH Type OD in my Gt which is leaking a decent amounto of oil as can be seen by the rearward spray pattern ending on the RH front side of my fuel tank. It is not engine oil as level has not changed. When I first look at it I see the typical wetness at the bottom of the gasket cover plate. I cleaned everything as best I could on the tranny and OD and drove it again for another 100 + miles. Jacked it up and see the oil at the gasket plate again. I also have seen a drop of oil at the rear flange seal. I let is sit for a day or so but see no dripping, everything underneath is still dry after I cleaned it again.
Any ideas of what is leaking prsumably under pressure?. I figured I would replace the main filter/gasket but loosened the screws and the cover won't budge, someone must have cemented it closed. As it is aluminum I do not want to start prying with any sharp objects. Any suggestions?????
Thanks
Mike
MK Mike K

Mike,

The drip on the rear flange seal looks as relevant to me.
Under way it could be many drips ending up everywhere. Leaking oil seals are often caused by worn out bearings.

Pierre
P.Y.A. De Rouck

Mike,
I've just stripped my o/d down completely and the gaskets all needed that little extra shove with a sharp edge to get them moving. Not sure which one you suspect but be careful with the larger one as there is a delicate mesh filter behind it.
In the past I've used a good gasket sealant else they can leak if they're not done up carefully and evenly, as you can imagine with them being only relatively thin aluminium.
The rear seal is usually pretty good as long as the rear bearing or prop are still running true. I've just changed my seal as I was there but the old one looked good after 30K plus.
Rihard
Richard Coombs

Guys
The drip on the rear seal could have come from elsewhere. I looked closly in good light at the seal and it looks in good enough shape,no nicks, it's in even and the flange has no side to side play. Looking at the main gasket/seal I see the gasket is pretty thick so I should be able to get something sharp in there to get the cover off. I have a new gasket/filter in front of me, not sure if it's the new and improved version? Tkhis one is NOT easy to pry apart and it has a sticky substance inbetween the gaskets, if you press them toghether they stick ..Thanks
Mike
MK Mike K

I've had trouble in the past with the kind of new gasket/filter you describe. There's a better kind in which the mesh is embedded in the gasket material but I'm not sure now where I got that one. I'd be tempted to prise apart the new one you've got and use sealant between the two parts to make sure the seal is good - my theory is that oil leaks past the wires of the mesh.
Miles Banister

Miles
I have read thru many archives on the subject and most agree that is what happens and that there is a better gasket/filter out there somewhere?
Most of the time though owners are saying they can see oil dripping from around the area/screws while the car is sitting, mine is not doing this so even though I should probably change this filter/gasket I am thinking my problem may be some place else on the OD.
Thanks
Mike
MK Mike K

Since this area sees 450 psi it is probably the culprit. It has always been a problem area to seal. I use a small amount of Hondabond (3M Bond) on each side of the filter/gasket assembly to control this annoying leak. It is available from motorcycle dealers and is far superior to silicone which tends to migrate into the od and clog small passage ways. RAY
rjm RAY

Are you talking about the sump gasket and filter? That should be a single item, which may well be made by sandwiching the mesh filter between two pieces of card, and may well delaminate when you remove the sump (one of my two did). But it is a single item. I used a smear of Hermetite red on both sides, and it is important not to overtighten the screws or it will warp the 'cover' and never seal.

The only parts at 450psi are the pump, pistons, solenoid and relief valve. The sump and its filter/gasket aren't.
Paul Hunt

Paul
Yes the sump gasket/filter. I would have to install a new one because getting the old one off will definatly destroy it as my cover plate is stuck
Mine must be dripping while the car is moving and/or in OD. Car has set level for 2 days now with no signs of dripping?
Mike
MK Mike K

It's possible the casting itself can leak. I was told that the casting can be so porous that oil weeps through it. And you think it's coming from somewhere else due to the slow leak and gravity.FWIW.
Samuel Sullivan

If you can puff talc or similar onto the cleaned area I'm told that reveals the source.
Paul Hunt

Great idea Paul!
Samuel Sullivan

This thread was discussed between 26/09/2009 and 29/09/2009

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