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Discussion Starter · #1 ·
im replaceing mine this week ..I have always worked with the old pontiac rope seals so this is a little new to me ive heard differing opinions .

.do the rubber seals install flush with the cap and motor or do you off set it a bit by pushing it in a little bit extra on one side and do the same with the cap to match them up ....if this is true how much do you off set it ..or was this just crazy talk .?

the best walk thru i found on the forums didnt mention any off setting ..i wanted to make sure it wasnt just understood and common knowledge and im out of the loop from all those rope seals ! =P
 

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You can not lose by just following the manufactures installation sheet.
 

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If you offset the seal, watch you don't slice the rib off the ID of the seal where it mates to the block. That's part of the seal.

I posted some time ago a step-by-step how-to on RMS replacement. I can't get the search thing to work from where I am to link it. Maybe one of the mods can? Please?
 

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Rear Main Seal The easy Way!

Basic, easy to follow, do it once rear main seal change.

Once you have the pan down, remove the oil pump and pickup. Remove the rear main cap. The lower half of the seal is right there. Don't scratch the bearing. Take a small screwdriver and pop the lower half out of the cap, then use the screwdriver, (I have one that I did a little bit of grinding on so it's got a better flat end) and push on the exposed end of the upper half of the seal. (If you have a brass drift you can grind to fit that's better!) You may have to tap it a little bit to break the upper seal loose. Drive it out until you can get a good grip on it and then just walk it on out. Now the old seal is out, clean the block and the seal groove with something like brake cleaner, just hose it out really well.

The trick part is next. GM and the aftermarket have 3 different widths of rear seals. The difference in them is from the dust lip on the back to the wiper lip on the forward side of the seal. The best (and widest one) is the one you need to find. The biggest distance between the two lips. You may have to hunt for it. GM had them all under the same part number, but there are different ones. The side of the seal that is "UP" in this picture is the "FRONT"




Take the rear main cap to your bench grinder and use the wire wheel on the mating surfaces adjacent to the seal. Look at the second picture. Where you want to buff the cap is where the sealant is applied. Don't get so far forward to catch the bearing. Buff the cap, get it really clean. Then hose it down with the brake cleaner too. Let it dry while you install the upper half of the seal.



In the package there is a little plastic "spoon". Use it to install BOTH the upper and lower halves. Put a little bit of grease on the lips of the upper seal. If you don't, the rib on the inside of the seal gets sliced off and will seep underneath the seal.


Once you have the lower seal in place, wipe a little bit of grease on the lips of that seal too. Apply a very thin coat of form-a-gasket or an anerobic sealer or something like that on the cap next to the seal. (RTV is too thick and the cap may not seat (register) in the block correctly.)
Look at the pictures here and you can see the proper place for the sealant.
Install the cap, torque to specs and install the oil pump, and pan. Use a dab of RTV at the corners where the gasket turns to go over the cap or timing cover. Do this on both the old style 4 piece gaskets AND the new one piece..



I've done literally hundreds of rear main seals over 15+ years of working for Chevy dealers and NEVER had to do the same one twice.:D

I've seen lots of posts that guys have offset the ends of the seal- GM didn't design it to be offset. Look at the groove on the back of the seal- that little rib in there is part of the seal. Slice it off and the integrity of the seal is suspect. Not to mention that that little bit of rubber is now got to be someplace.
 

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Discussion Starter · #7 ·
ok thanks that helps i suspected the off set was just a personal preference ill play it on the safe side and not get to creatyive on my first small block chevy rear main ...im the guy that would slice it! :thud: hehe

thanks again;)
 
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