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Rear main oil seal recommendation needed...

Mopar Muscle
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Rear main oil seal recommendation needed...

HooToTheCore HooToTheCore
New User | Posts: 7 | Joined: 12/10
Posted: 02/17/12
08:12 PM

I'm rebuilding a '71 440 (on engine stand). I've got all my machine work done and am ready to set the crank.  I have both a rope and a rubber rear main oil seal and I want to know which will work the best?

This is my first rebuild, so any advice on sealing the seal cap would be welcome.  I have the old cap side seals and two new paper side seals.  Should I use the old side seals with silicone sealant or the new side seals soaked in mineral spirits as described in the seal installation instruction?



marcohotrod340 marcohotrod340
Enthusiast | Posts: 470 | Joined: 09/08
Posted: 02/18/12
08:44 AM

the rubber seal is much better. new side seals are better than used, and some silicone is a good idea. read some more tech from this site about big blocks.  

waynep7122 waynep7122
Enthusiast | Posts: 643 | Joined: 08/09
Posted: 02/18/12
09:24 AM

there are several threads on leaky rear main seals..

there are a bunch of offsite links on this thread...

there are several more..   use the search link to the right of the active posts link above left...  

type in rear main seal..  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 02/18/12
10:40 AM

Rope seals? I can tell you I have never seen one that didn't leak. Stick to the newer rubber seal and some silicone on the side seals, you will have much better success..  

Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 03/02/12
08:10 PM

I was putting a rear seal in a 383 on the engine stand. It said to soak the side seals in mineral spirits, but not how long. After 15 minutes soaking they were swelled up so big we couldn't get em to fit in. I took the whole unit back and got another new one.(For free-exchange} This time-no soaking! they were pretty tight right out of the box. So we put a few drops of mineral spirits on after assembly, and it seems to be holding ok. The rope seal was used back in the stone age lol. So definitely use the neoprene seal, With some silicone at the seal cap mating surface.  

marcohotrod340 marcohotrod340
Enthusiast | Posts: 470 | Joined: 09/08
Posted: 03/20/12
04:17 PM

maybe mill .010" or so of the seal retainer