BLOWN REAR MAIN SEAL

1994 Jeep Cherokee

Tiny

jeremy76

April, 16, 2012 AT 6:47 PM

Hey guys after getting this jeep running I found it has a blown rear main seal, is there any tricks on how 2 change it with out dropping the whole crank?

the crank has a big flange outside of the rear bearing cap which wont let you have access to the seal!

5 Answers

Tiny

caradiodoc

April, 16, 2012 AT 7:32 PM

I had to guess which engine you have so I picked the V-6. The rear bearing cap has to be removed. The lower half of the seal is in that cap. To remove the upper half, a tool is made that threads into the end of it, then you pull it out without having to lower the crankshaft.

Tiny

jeremy76

April, 16, 2012 AT 8:15 PM

Its the 4.0!I see what ur sayin but theres really no way to put the upper seal back in safely without ruining the seal, I cant even get to the top seal even with the bearing cap removed?

Tiny

caradiodoc

April, 16, 2012 AT 10:20 PM

You should be able to see the ends of the upper half of the seal. The tool is like an awl with a self-tapping thread on the end. You run that into the end of the seal, in the middle, then use that to pull it out. Having a helper turning the crankshaft at the same time may help. You might also be able to grab it with a needle nose pliers.

To install the new half, the tool looks like a "Chinese finger". You put the end of the seal inside the braided string, fish the end over the crankshaft, then pull on it to run the new seal in. Very commonly the seal will be too long to allow that pull-tool to make it all the way around so it can be removed, then you cut the seal to fit.

Tiny

jeremy76

April, 18, 2012 AT 2:50 PM

Thanks for ur response! But with this type of seal u cannot cut to fit, the seal is exact fit and has 2 pieces, the upper has to go all the way around the top of the crank, the bottom one has to fit in the 2 grooves in the bearing cap. Other wise u risk a leak and I know I dont want 2 do this again!Thanks for ur time jeremy

Tiny

caradiodoc

April, 18, 2012 AT 7:32 PM

The cut-to-fit seals are made extra long to allow the pulling tool to come all the way out so you can release it without having to push the seal backwards a half inch to center it. Even if yours isn't like that, it should appear to be just fuzz too long, perhaps no more than 1/16". That's to insure both joints butt up against each other to form a good seal.

You might look at putting a very thin, light coating of silicone gasket sealer on the joints to seal the gaps. More is not better because then the sealant can squeeze around the lip of the seal and allow it to wick oil around it. I too hope you don't have to do this again.

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