440 Rear Main Seal Replacement

[tyallis]

I have finally worked up the energy to pluck the 440 back out of my car, to address a few things that I FUBAR'ed a couple years ago when putting it together. One of the issues being the rear main seal that has started to leak like a sieve.

Question is: what are the recommendations for replacing the top RMS with the crankshaft installed? Or, would it be possible to lift the crank out to replace it with the pistons/rods still in their bores?

Just trying to strategize my plan of attack... Thanks.

 

[FrnkNsteen]

I haven't tried it, but from what I have read, I think you can drive out the portion in the block without pulling the crank.

Do you know if it is leaking at the crankshaft interface, or is it leaking at the sides of the retainer where it seals against the block?

This thing....

 

[tyallis]

No idea as of now. Motor is still in the car at this point; I will take a close look once its flipped over on the stand.

 

[bherman]

I have finally worked up the energy to pluck the 440 back out of my car, to address a few things that I FUBAR'ed a couple years ago when putting it together. One of the issues being the rear main seal that has started to leak like a sieve.

Question is: what are the recommendations for replacing the top RMS with the crankshaft installed? Or, would it be possible to lift the crank out to replace it with the pistons/rods still in their bores?

Just trying to strategize my plan of attach... Thanks.

Hi tyallis, if no silicone was used in the block groove where the top half of the seal sits when you assembled the engine the seal is relatively easy to remove. Use a small wood dowel or aluminum rod to push on the end of the seal, once it moves and pops up on the opposite you can grab it and pull it out. Turning the crank may help with removal and installation. This operation can be done with only removing the seal retainer cap. Do not use a steel drift to push on the seal, even if you don't scratch the seal surface on the crank you have to be careful of the groove surface. As FrnkNsteen indicated check the end seals on the retainer cap, that's where my leak was. Hope this helps, Brian

 

[tyallis]

Thanks bherman. What do you recommend, when sliding in the new seal into the block? Thin layer of silicone on seal/block mating surface? Assembly lube on seal/crank mating surface?

I am unsure if I used silicone on the seal when installed last go-around. If so (that'd be my luck), could a guy lift the crank out with the pistons still in their bores?

 

[khryslerkid]

It's all in a "Sticky" under engine, trans and driveline. Open the PDF for full instructions...

www.forbbodiesonly.com/moparforum/threads/looking-for-a-sticky-thread-on-rear-main-seal-replacement.127618/

Remember to use sealer in the recessed retaining bolt holes after tightening the bolts. Fill them to the top of the cap before installing the pan gasket.

 

[PurpleBeeper]

The other good tip I got when I re-did mine was to offset the upper/lower seals, maybe 1/8" or so, in order that the two halves don't line up with the seal retainer.

 

[Frank Mopar]

I did mine in the car with this one piece seal. Great customer service too

http://www.fastfishautoparts.com/Performance-Engine-Seals.html

 

[bherman]

Thanks bherman. What do you recommend, when sliding in the new seal into the block? Thin layer of silicone on seal/block mating surface? Assembly lube on seal/crank mating surface?

I am unsure if I used silicone on the seal when installed last go-around. If so (that'd be my luck), could a guy lift the crank out with the pistons still in their bores?

tyallis, if there is any sealer in that groove you have to get it absolutely clean. I'm not sure how much you can lift the crank before you run into problems, attempting that operation seems sketchy to me. Others here may have experience with this. A local seal manufacturers engineering department recommended lightly lubing the back side of the seal and using assembly lube on the seal lip, crank surface. Start the seal end in the groove and rotate the crank (in the draw direction) while gently pushing on the other end of the seal. When the seal is in the correct location put additional assembly lube on the crank surface and rotate the crank to assure the lip has plenty lube on it. hope this helps, Brian.

 

[Daves69]

FWIW, The TSB is in 70-25-7 pages 6 & 7 here...………
http://www.hamtramck-historical.com/1970-TSB-Index.shtml

 

[65-440]

Easy day, drive the top half of the seal out using a punch (without nicking the crank! ) while someone else is turning the harmonic dampner bolt. Sealer on the back side and lube on the lip of the seal, push it in as that same person is turning the crank again. Not a hard job at all ..

 

[tyallis]

Thanks for all the resources and words of wisdom. I'll give it a shot, and report back with problems. Regards.

 

[Fran Blacker]

In post#2 I like to kiss the 2 bumps where oil pan bolts are that face the number 5 cap. Friend had leak because they hit the cap.

 

[tyallis]

Fran Blacker,
That must be why it is recommended to remove that main cap, when installing the lower RMS block?