Rear Main seal replacement

[WyKev]

The rear seal on my 340 was obviously leaking so I thought I would replace it while it is on the stand. Pulled the pump, pulled the cap, still has the OE cork seal.

My dodge manual and my motor manual only show you how to do it with the crank removed. The problem is the block half of course. How do you get it out?

I can't believe you have to loosen/ remove the crank, but can't remember how we use to do them back in the 70's. Ideas? Thanks!

Oh, should I put a new high vloume pump on while I'm at it?

 

[swing69]

You have to remove the main caps and lift the crank off the bottom bearing halfs. The conrods can be left on, as the pistons never leave the bores.

Once up, you can remove the block side of the seal. When you say cork seal, I assume you mean 2 piece rope seal. Once you put in the block side, you can use the crank to seat it. Make sure its wet with some oil. The best seal is had when the seal is staggard (I like to do this....but sometimes its tough to get right). Meaning the seam of the two halves are NOT in line with the bearing cap / block line.

To get the stagger, you actually install the block side, seat it, then cut it flush with the block (if necessary) Some soft rope seals are this way, a more rigid seal, will be easier and a better fit. You do the same with the seal in the cap side. Once cut, push the block side below the block surface, the other side with stick up slightly. Then do the same thing with the cap, now you have the stagger when you install the cap. You'll also need an anerobic (sp) sealant under the rear.


Here is a link to a guy who does it on a 318 with the engine and trans in place. He doesn't stagger or trim the seal. http://www.pavementsucks.com/tech/rearmain.php

 

[green1]

They make a tool; Napa, snap on have it; It will push/pull the seal in the block out, just loosen only the rear main. a wire with chinese fingers.
Then cleaning and some sealant sliding it back in helps.