Rear Main seal on a 400

[Pclancy]

My 1977 Canadian Newport with a 400 had a new rear main seal on it when I bought it six months ago. When I asked the PO why, he explained that this seal replaced an earlier seal that was installed incorrectly--and which leaked. So maybe 2 seals in 2 years or less. He claimed the problem was fixed.

Not really, as the current seal is now leaking. I have a really good mechanic, so I don't think he will mess up the installation.

But any idea why all the problems with these seals? I hear they are the rope type. Is there a special trick to installing them such that they don't leak?

Thanks

 

[commando1]

Not to sound like a sleezy used car salesman, but this really is a case of
"They all do that".
A rear seal leak on Mopar big block after 35 or so years shouldn't be a shock to anyone.
And replacing the seal on these BBs is usually a 50/50 situation. Nature of these beasts. Especially if the seal was replaced without pulling the engine. Snaking in a new seal without removing the crank is iffy at best.

Special trick? Do it the right way, drop the crank, use a ROPE seal. Yah. It sucks.

 

[traintech55]

Stan is right (as always), by the time you go thru all the work to drop the exhaust, center link, and oil pan, you are not that far off the labor to pull the engine and do the job right, also how would you check for a groove in the crank with it in the car.

 

[MrMoparCHP]

Also I think people fail to seal the bracket to the block, yes there are a couple seals in there but stick some Ultra Black on all the edges of the bracket inside and out.


Alan

 

[70bigblockdodge]

Also don't line butt ends up with the retainer to block mating surfaces. Make sure the butt ends do not have bumps sticking up on them, does not apply to rope seals and your on your own. Why you would want to torture yourself with one of those is beyond me, maybe go to the slaughter house and get some cow hide and make your own wheel seals while you are at it.

 

[commando1]

Also don't line butt ends up with the retainer to block mating surfaces. Make sure the butt ends do not have bumps sticking up on them, does not apply to rope seals and your on your own. Why you would want to torture yourself with one of those is beyond me, maybe go to the slaughter house and get some cow hide and make your own wheel seals while you are at it.

Can I take it you disapprove of rope seals?

 

[70bigblockdodge]

I have never used one, would not know how to find one. Every one I have ever removed I look at it and say glad I don't have to do that and this should be in a history museum.

 

[detmatt]

I'm pretty sure the only way I would be able to stop the drip from the rear main on the Imp is with a rope seal.

 

[superfragl]

I always used new style rubber seal and never had a leak. Permatex #2 on all mating surfaces and a dab on seal ends. Also make sure the crank journal where the seal rides is not polished - it is supposed to have knurling on it.

 

[commando1]

And never use the 440 Source retainer
It absolutely will leak.

 

[detmatt]

As will the billet one they sell at Mancini's unless they made some improvements. What Ma Mopar used originally works the best imo.

 

[Pclancy]

As will the billet one they sell at Mancini's unless they made some improvements. What Ma Mopar used originally works the best imo.

The leak as it turns out was from the valve cover. The oil would run down over the bell housing and make it look like it was the main seal. Fixed the valve cover leak. We shall see. Many thanks for all the great advice!

 

[traintech55]

The leak as it turns out was from the valve cover. The oil would run down over the bell housing and make it look like it was the main seal. Fixed the valve cover leak. We shall see. Many thanks for all the great advice!

The cursed valve cover leak again.

 

[detmatt]

You're a lucky guy!