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post #1 of (permalink) Old 04-16-2003, 08:54 PM
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How hard to change main seal in YJ?

The day before I went mudding I checked under my jeep to make sure nothing was falling apart. U-Joints ext. What I found was that I am leaking a little oil from what looks like my main seal. (The seal in between the engine and the tranny) At least thats what I think its called. Any way. How much work is involved in changing this so that it dont get worse. Anything anyone has to say would be appreciated.
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post #2 of (permalink) Old 04-16-2003, 10:27 PM
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Re: How hard to change main seal in YJ?

When I did it, it wasn't very hard. The tricky part was actually installing it correctly(which I didn't, as it leaked worse afterwards). I also didn't use the correct tool for the job. I thought if I was careful, that I could use a steel punch. BIG mistake. Before I knew it, I had knicked my crankshaft. Luckily after using some emery cloth on it, it's all better now. So if you do do it, take your time, make note of how the old one is installed, and use a brass punch. Other than all that, it's just a matter of popping off the oil pan, taking off the rear main cap, and going about your business. But if I'm missing a step, someone please let me know.
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post #3 of (permalink) Old 04-16-2003, 11:09 PM
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Re: How hard to change main seal in YJ?

There's a few tips to be gathered by looking in the manual or at the fel-pro installation instructions. Even there, there's some conflict between the two instructions.

A little liquid soap on the backside of the upper seal helps to slip it in place. Be carefull not to cut the seal on the sharp edge of the block as you push it in. Loosening off the other main bearing caps will help generate a little more clearance to slip it in place. Some say to put a dab of sealant on the ends of the seals, some say not. I don't think it's necessary, as it looks like there is pressure against the ends to seal themselves. A little sealant on the corners of the bearing cap where it's chamfered is also recommended by some, and I've always done that.

See if you can dig yourself up a manual. The instructions are pretty much universal, other than some other makes use a rope seal and you have to trim the ends.

Put a little oil on the face of the crank that rubs against the seal so that it doesn't start out dry and damage the seal.

I've always used the Fel-Pro seals, but I'll tell you the seal gets hard and brittle quickly. A new seal is soft like rubber, a two year old seal you can snap the seal edge right off it, and in fact the last two I removed, that edge was broken partially.

There's one bolt on the passenger side of a 258 oilpan thats hard to remove, and you may need to loosen off the motor mount and pry up the engine to get at it. I never put that bolt back, and have had no problems at all with leakage. Just make sure your pan edge is straight, and don't over tighten the bolts and distort it.
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post #4 of (permalink) Old 04-17-2003, 04:53 PM
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Re: How hard to change main seal in YJ?

Errr ...I only got through a little of the others post here before I checked your profile. You have a 2.5? If so you don't have the type seal (two piece) that they are referring to. For some reason, along with the other drivetrain anomolies (different trannies, spline counts, etc.) that AMC put into the mix when they merely hacked out two cylinders, they use a one piece rear main seal.

You have to either pull the trans/t-case ...or pull the engine.
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