rear main seal

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mopar head

mopar head

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Been chasing an oil leak and come to the conclusion that it is the rear main on my new/rebuilt 440. I had the machinist build the bottom end, well he hosed me . The engine is back out on the stand, he didn't use any side strips and only got sealant down 1/3 on the sides. the seals themselves look a little suspicious, rough cuts etc.
So my questions to those who had to go through this mess, can new seal be slid under crank? Will crank have to be lifted?
Any tips are appreciated, I want to do this once and right, Don`t want to spend for the fancy billet retainers if the oem will work fine with care on installation.
 
I was able to replace the rear main on my BB twice while it was in the car. The upper half seal will slide around the crank. I used a length 1/8" aluminum tube that I bent a curve in to push the seal. The reason I say twice is the first seal failed. In my case the OEM retainer did not have enough "push" against the lower seal. I used rtv in the cavity of the retainer block where the bottom seal fits and let the bottom half of the main seal to just sit in there while it set. The idea was to give the seal a little more "push" against the crank. This did indeed work for me but I'm not suggesting it for everyone. Good luck, these can be a pain.
 
You can install a new seal without loosening the crank. Be careful to protect the back of the seal so that you do not shave off the raised portion of seal as you push it in. Put as much sealer as you can on the sides of the retainer and also seal it on the rear of the retainer. Its been a problem for years but with the new kits missing the side strips the problem is worse.
 
Done em in the motor a couple of times.
I have a 1/8 shaft screwdriver cut off flat on the end to get it started coming out.
Couple of light taps and it's on the move.
 
mopar head said:
You guys use any sealant behind the seals?
Click to expand...

I just wipe the block side with a thin film of RTV and the crank side with a drop or two of oil to get it to slid back in place nice and easy.
Some of them come with a little shoe horn wannabe piece of plastic to help protect the our edge going back in.
 
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pay a man 2k and get a seal job like this:soapbox:
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after two attempts to stop the rear main leak on my hemi...I bought a billet rear main seal kit from mancini....took 12 thou off and installed while the motor was in the car. Not a drop/leak since.
 
I haven't done one in a car, but the Mancini RMS is the way to go.

Holy Jebus with that main seal job. I saw less sodomization when we raided a covert gay bar in Iraq. S/F....Ken M
 
The sides of the housing are clearly done wrong, but also the install of the seal it's self could have been improved upon. Chances of the ends of the seal lining up are hit and miss. Being off a hair and there's a leak. If you "clock" the seal so that about 1/4 inch of one end is still exposed, other end below surface of the block, and do the same with the aluminium housing then the seal it's self will act like it's own aligning devise.
 
famous bob said:
just went thru this, know how aggravating it can be. "be sure" to run at least one pcv valve it will help!
Click to expand...
I did,I did..

terzmo said:
after two attempts to stop the rear main leak on my hemi...I bought a billet rear main seal kit from mancini....took 12 thou off and installed while the motor was in the car. Not a drop/leak since.
Click to expand...
You feel it did`nt provide enough compression?

EchoSixMike said:
I haven't done one in a car, but the Mancini RMS is the way to go. I may bite the bullet and fork it over, heard nothing but good with these retainers.

Holy Jebus with that main seal job. I saw less sodomization when we raided a covert gay bar in Iraq. S/F....Ken M
Click to expand...
Thanks for the chuckle, I need all I can get with the frustration of this rebuild.

Max1196 said:
The sides of the housing are clearly done wrong, but also the install of the seal it's self could have been improved upon. Chances of the ends of the seal lining up are hit and miss. Being off a hair and there's a leak. If you "clock" the seal so that about 1/4 inch of one end is still exposed, other end below surface of the block, and do the same with the aluminium housing then the seal it's self will act like it's own aligning devise.
Click to expand...
Read this elsewhere, and was planning to try that.
Looked like the seals were trimmed with his teeth.
I could forget the fact that he went 2 months over the stated month to build this thing, but with this, I`ll refer him to no one, I left a message about the deal and guarantee he will not return the call.


Thanks fellas..
 
mopar head said:
I did,I did..

You feel it did`nt provide enough compression?

Thanks for the chuckle, I need all I can get with the frustration of this rebuild.

Read this elsewhere, and was planning to try that.
Looked like the seals were trimmed with his teeth.
I could forget the fact that he went 2 months over the stated month to build this thing, but with this, I`ll refer him to no one, I left a message about the deal and guarantee he will not return the call.


Thanks fellas..
Click to expand...
made it a bit tighter at the bottom.
 
The exact same thing happened to me! He installed the seals even with the block/retainer surfaces and it pissed oil everywhere even on the dyno - dyno owner was not to happy about that..

Use only Permatex Ultra Black RTV -

Buy the oem rubber seals not rope, and the silicone side seals

Assuming you have it all torn down and cleaned as best you can get it, dry as well use lots of brake cleaner. Put a dab of ultra black RTV on the side of the seal that will sit under the crank(under the surface of the seal retainer) put another dab on the other side of the seal once it's in position - install the top seal in the block under the crank with one side sticking out about 3/8"

Cover the sides and bottom of the block where the retainer will mate with the block - cover the sides/bottom of the retainer as well with Ultra Black install the seal in the retainer in the same orientation as the other side is in the block again dab of silicone on each end of the seal.

Install the side seals on the retainer half way down on the retainer(so they stick half way off the retainer and hit the block when you have the retainer about 1" in the block), slide the retainer in the block slowly watching the side seals and making sure they stay not only lined up but end up flush with the oil pan rail when the retainer is all the way down (with the bolts)

Wipe away any excess silicone and use it to seal the flex plate side of the retainer, and the oil pan rail (small gap between the block and retainer). Rotate the motor as soon as you finish it to make sure no silicone dries to the crank under the seal

Use Ultra Black on the oil pan gaskets as well - both sides of each (I have 2 for a factory windage tray)

Lastly don't put any oil in the pan for AT least 3-4 days to let it all cure..

I did this on my 383 and it doesn't leak a drop of oil.. ATF though... LOL but I know why it leaks that - bad drive shaft yoke (the center was punched out at some point and I JB welded it bad on and it leaks)
 
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