Rear Main Seal

[James_Douglas]

My nice new engine is weeping a little oil at the rear main or the rear pan gasket.

What if anything can be done, short of pulling the thing out if the rear main is not sealing correctly.

Best, James

[Normspeed]

Strangle your machinist. Mine does the same thing.

[greg g]

In my experience after a replacement of one in my old engine, and a new one in my 2500 mile old rebuilt new (1956) engine, I have concluded that a rear main seal leak must be a MOPAR Flathead Character Flaw, as in both cases, newly installed parts, began to leak nearly immediatly. Granted both are much bettter than what they replaced, but non the less, still allow the slow but steady migration of lubrication. Perhaps there is some sort of force field set up by the clutch that sets up an irresistable attraction to the engine's oil, which the design of either the new or old style of seal is equipped to deal with. Think of the oil drops as your car's way of leaving a breadcrumb trail to find its way home.

[jd52cranbrook]

I tried a rear seal from canada, not the rope type but rubber, and still a leak.

[Guest rockabillybassman]

I wonder if you took the main cap off, removed the seal top and bottom (can be done), and installed shims so that the seal presses harder on the crank. I did this with an old seal, and it did'nt work but I think my shims were'nt thick enough. I cut them out of gasket paper, but I should have used something maybe about 1.5mm thick. I will do this one of these days, so it will be interesting to see if it works.

[jd52cranbrook]

Sure would like to find a cure. I have the motor out now, prime time to fix it.

[James_Douglas]

My engine is near new. The crankshaft IS new not a re-grind. The rear seal area was polished (new style) when I had the crankshaft polished. The seal is new type not rope. I was careful as can be. Perfect assembly. I am hoping it is the rear pan gasket or the seal on the outside of the rear main cap that is the problem.

I guess I will have to jack it up and drop the pan to try and figure it out.

James

[bob westphal]

Greg G is right. The old engine designs weren't sofisticated enough to eliminate minor oil leaks. In those years people were glad to have a car that was dependable and didn't worry about oil spots on the drive. I have a lot of trouble with clients because they think that their restored car shouldn't leak oil because their 2004 rice rocket doesn't leak. Put a piece of card board or floor dry under your car. Drive 'em and enjoy!