Rear main seal leak

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tp tbird
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Rear main seal leak

Post by tp tbird » Sat 6. Nov 2010, 09:42

I have posted the trouble I had with my 430 tbird with a rear seal leak before after I had it rebuilt and it is still leaking 400 mile on it.What I was wondering if anyone could tell me if it is possible to see or away to check where it is leaking from with out taking the oil pan off or the engine out?The guy that rebuilt it put a wick seal in it after the neoprene one didn't work ,that only slow it down I have had to take the engine 3 times now.I have been looking around at posts and books and thought it might be the side seals on the rear main,maybe he didn't install them right,but don't know.If I could get it checked somehow to see where the oil is dripping from without major surgery on it.The re-builder suggested a dye in the oil,but I don't know if there is enough room to see it back there if the car is up in the air to see if it is from the side seal or the rear main seal.This guy only has a machine shop so he can't do anything with the engine in the car.Any suggestions?

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Theo
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Re: Rear main seal leak

Post by Theo » Sat 6. Nov 2010, 10:21

Rear main seals are tough to diagnose. I see no other option than to lift the car up and taking off the pan. An other sneaking suspicion that springs in mind are the oil gallery cups further up in the block. If for some reason it wouldn't seal, it would gives you a false track on your diagnostics. Those usuall seal well and for the engine builder it's hard to do a mistake here, but you never know. You would have to rake off the trans to check this out, grrrrr!!
viewtopic.php?f=2&t=610

Sometimes a leaking rear seal will work better after a while. That's probably due to grime and dirt that blocks the flaw as the miles go by.
There was an aftermarket neoprene rear main seal discussion just recently. As far as I remember those are not continued anymore. Not sure. may s.o. else can throw in more info on that. I'm curious.
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tp tbird
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Re: Rear main seal leak

Post by tp tbird » Sat 6. Nov 2010, 14:48

I had the guy put in a neoprene seal in that I had to get from a tbird parts book for a 430 engine . The 2ND time I took the engine out was due to a oil plug in the rear of the engine he said and he fixed the plug then I had to put it in and together ,when I started it it was still leaking under there.So he took it to a shop next door and took the trans out and dropped the pan and tried a small brass shem ,that did not work so back home to me to take the engine out again to put a wick seal in.I got it back to put it back in and together and started it and it still was leaking but not as bad a drip about 1 every 10 to 15 seconds.Now with some miles on it and it is still that way.

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Theo
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Re: Rear main seal leak

Post by Theo » Sun 7. Nov 2010, 12:05

Rear end seals left me helpless more than once. I would drive the car for a few weeks and months and see what happens. It might get better if you're lucky. Sorry, can't think of an other way to solve the problem. Also keep in mind that these engines were never perfect.
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Treinarts
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Re: Rear main seal leak

Post by Treinarts » Mon 8. Nov 2010, 12:43

I had an oil leak from a 429 Ford. Made a small splotch when running. Replaced 2 rear main seals. Couldn't see exactly where due to the oil being all over the inside of the bell housing.
We pulled the distributor and used a drill to turn a small socket (5/16 ?) on the oil pump quill, then we pulled the oil pan. We turned the drill on, it spun the oil pump, and were able to watch the oil seep out of the back of the cam bearing plug. Felt smart and dumb at the same time. Solved the mystery anyway. TJR

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