How to replace rear main seal?

[CROCKETTBOONE]

My only suggestion it to let the oil drain overnight or longer. Nothing worse than oil dripping on your face.

[FSJ Guy]

Also, depending on our Y pipe configuration, plan on dropping the Y pipe in order to remove the oil pan AND access the rear seal. If they haven't been off recently, the manifold studs and nuts will be frozen together. PB blaster those suckers for a good week before you start. Otherwise, you'll be removing your manifolds to take them into the machine shop to have broken studs removed. AMHIK.

Watch your seal orientation and lube the seal with fresh oil when you install it SLOWLY.

Have fun!

[Lindel]

And bring LOTS of rags/cleaning supplies to the show! You'll spend more time cleaning before you put it back together than you did fixing it!

[Driftwood]

"READ THE INSTRUCTIONS IN THE JEEP SERVICE MANUAL AND FOLLOW THEM TO A TEE. SOMEONE HERE CAN POST THE PAGE FOR YOU."

Soooooooooooo, can someone please post the Service Manual Instructions. That way we can all be in the know!

[Casey]

what? you guys are making it sound hard! its not. your mechanic friends saying rebuild or get a new engine must think it has a one piece rear main seal and in that case you would need to pull the tranny or pull the engine, but AMC's are two piece seals so like most have said just drop the pan take off the main cap and loosen the next one. pull off the bottom part of main seal and then use a punch or something similar to start the top half of seal . then do the reverse for putting it back on. make sure u get the lip on the seal facing the correct direction and be sure to torque all bolts back to specs. the biggest pain is getting the pan back on for sure.

Yeah...what he said. The pan removal and installation is the hard part.

DO NOT use a steel drift to drive out the upper part of the seal. Even if that's all you have on hand. Plastic or brass ONLY. If you knick the crank it will leak at the RMS forever.

[JERSEY JOE]

REAR MAIN SEAL

Don't underestimate the importance of the application of sealer on the chamfer between the rear main cap and the block.

IF IT IS NOT RIGHT IT WILL LEAK.

Of you do it without the sealer it will leak.


I have done lots of these in the past 35 years and yes I have had to do some of them twice. The " in the chassis " repairs are the hardest since you need to get the block parting surface clean and dry. Do not put sealer between the block and the cap ot it will increease the bearing clearance.

Also when you complete the job try and let it sit overnight so that the sealer sets up. If you start the engine too soon after replacing the seal it will leak past the uncured sealer...

[temps425]

lol!

these guys are halfway right on how easy it isnt. lol

here is the way it usually happens:

go to store buy parts,
stop at next store pick up drinks of choice
go home, drain oil
drop pan
drop rear main bearing cap

next step is to spend 3 days dropping crap on your face while trying to get the frozen in place rear main seasl out of engine.

once it is finally out though it is a matter of rolling new seal in and bolting it all back up (please remember te re-install drain plug) and filling wiht oil

eric

[Driftwood]

FSJeep13
So did the rear main seal get replaced yet?

[Mark Wilde]

ONE FINAL NOTE

I'm surprised no one said this yet...

When installing the upper seal, MAKE DURN SURE you do it carefully and DO NOT "shave" the seal on the block. You'll know what I'm talking about when you do it. If you nick the top part of the seal and shave rubber off, it'll leak till you do it again. I did nick it, so I pulled it back out and siliconed the pi$$ out of it and put it back in. Got lucky, no leaks.

Good luck, it's really not as difficult as it is intimidating.