Rear Main Seal

Just got an '88 Cherokee with the 4.0L Renix engine for my son....was a deal at $800. Anyway, it is leaking through the rear engine main seal. I'm wondering how difficult it is to replace in my garage (without a hoist). I've got the Chilton's manual...and seems to be tedius (removal of starter, removal of engine mounts/raising engine, disconnect exhaust from manifold, etc.). Anyone here done it? Is it feasible in a garage with hand tools, or should I just bite the bullet and pay the $250-300 it will take to have it done at the shop?

I'm fairly mechanical...have necessary tools (I think), and also have ramps I could use to make it easier to get underneath. Any help is appreciated.

Its not that hard and the chilton has some steps in it that you dont really NEED to do...like removing the starter, exhaust, motor mounts...the ramps will help you a lot.
I guess first thing would be to make sure its the rear main...both the valve cover and oil filter adapter o-rings tend to drip to the rear and look like a rear main leak...
Also check the positive crankcase ventilation system to make sure its functioning right. When I fixed the vacuum on my wifes the rear main slowed its dripping a lot. Still leaves a spot on the garage floor but not as bad...
And if your going to put in a rear main you might consider a fresh oil pump while you've got the pan off. All stuff you could do with hand tools.

Of course it can develop in to a real pain in the a$$ if the seal wants to be difficult...got anyone you can call for help if it gets difficult?? Always good to have backup that knows more than you.

I've done two of these on XJ's in the last 3 months, one on my 89 and another on a 91. Take it to the carwash first and give the underside a good washdown, concentrating on the oilpan and tranny area, if you have no lift on your rig then take your ramps to the carwash for best results.

Book recommends using a brass punch and a mallet to tap the seal out of the block. With the punch, make sure you are tapping on the metal part of the seal and not the rubber. The seal on the 91 wasn't cooperating so I took a nailset to it and it popped right out....but we also loosened the main caps too, but avoid this if you can. It doesn't hurt anything if you know what you're doing and torque everything back down properly, but it adds a layer of complexity to the repair that can be avoided.

Use a 1 piece rubber gasket on the pan for best results and if the old gasket is stuck to the block, try using a heat gun or propane torch (type used for soldering copper pipes) to soften it, then scrape it off with a putty knife or gasket scraper. Clean residue with brake parts cleaner before reinstalling.
Good luck.

I didn't do the rear main seal but I did a oil pump.The oil pan took about 20 minutes to get off after all the bolts were out. I don't know why but all of a sudden it came out. But putting it back on was a real pain, it just wouldn't fit! Pryed the engine up tried to lower the front axel more and finally got it in position. You don't need to remove the starter, belhousing cover or exhaust pipe as the Haines tells you. BTW after lowering the pan before sliding it out you have to remove the oil pump and drop it into the pan. Get a new oil pump gasket or one comes with a new pump. Then put the pump in the pan before putting it back in then bolt the pump on before raising and bolting the pan. But as others have said make sure it's not the valve cover and or oil filter housing "O" rings. Also clean the crank case breather as another mentioned. It's the rear hose on the valve cover. Just remove the plastic pipe from the fitting. If you try to remove it from the valve cover it will brake. Make sure the small hole is cleaned out.

JoBo

Cool....thanks for all the good advice. I think, based on the advice given here, that I will attempt it at home...reserving a weekend for the work.

Let us know how it goes...I have all the parts to do mine sitting in the garage, I just keep putting it off. It's not getting any better and drips right onto the exhaust pipe. Smokes more than I used to!

This is another one of those:
"I read some where"posts...
I did read that if you remove the top shock bolts,then support the vehicle
on the front sub frame,it will make removel of the oil pan easier.Supposed to give about 2-3 more inches of drop at the front axle....

churky89 said:

This is another one of those:
"I read some where"posts...
I did read that if you remove the top shock bolts,then support the vehicle
on the front sub frame,it will make removel of the oil pan easier.Supposed to give about 2-3 more inches of drop at the front axle....

Click to expand...

correct- and even better, if you place a floorjack inbetween the axle and the lower frame on the drivers side and lift until its as far as it can naturally go, you`ll get "just enough" room to pull the oil pan without worrying about the pump being in the way-
On a normal, non-lifted XJ-theres just quite not enough room to do it without the extra umph of the jack, but theres plenty of room for frustration and pain, twisting and swearing- I swear it looks like theres just enough room to get that pan out!... :rattle:

buy a new oil pump-
replace the rear main, have a spare on hand.
do the valve cover gasket for fun
if its 10+ years old, do the o-rings in the oilfilter houseing for insurance.

DONT forget to fill the little holes with RTV on the front cover where the new pan gasket sits(if useing the rubber gasket)-failure to do so will result in nice little leak that requires you to start over.

you will be "leak free" and proud.

I've had this link bookmarked for a long time:
http://www.jeepin.com/features/rearmain/index.asp

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