Rear Main Seal Nightmare!

so after reading the write up on the rear main i get my tools together and plan to stop that oil leak once and for all.

Now i have to say i did not have any real fear about this job as the write up looks pretty straight forward and have been working on cars as a hobby for a few years.

So let the nightmare begin.
Well the first issue was the fact that the front rear seal had been leaking for about 3 years and the PO did not fix it ( i did last week) so the whole motor from the balancer back was just a mess of grease and caked on grime that even the pressure washer would not move.

I jack up the front end way high on some big stands i use for the truck and loosen and remove all the oil pan bolts, its take about 45 min to do this because of all the crud stick to everything.

Then i try a few blows with a rubber mallet to loosen the pan,, nothing.. a bigger mallet... nothing.. i end up hammering in in a pry bar between the block and pan and then using a smaller hammer to drive it all the way down the sides of the case to get the seal to give!!!

Once the pan is loose i can see no way of getting this out the back of the motor. The front axle sits where is simply cannot come off. I remove the sway bars to give me a little extra room and the axle is now at full droop and still i am missing about 2 inches of clearance.
I finally give up on that plan, remove the drag link and rest of the searing, unbolt the oil pan pick up and remove it from the front. on a side note watching the cheep cherokee build on Trucks they did the same thing perhaps its an issue with the 87's?

Before moving any further i spent over an hour (yes and hour) getting what was left of the rock hard, and i mean rock hard gasket off the bottom of the block and cleaned out the pan which was to my surprise almost sludge free. The gasket has set to hard i ended up using a steel scraper for floor tiles as the razor blade one i had just broke the blades.

then onto the seal replacement itself!! I pull the bearing cap off and this is where i stated to worry. getting the lower half of the seal out of here with it on the bench was a bitch, it took some real force and the cap being held in a vice and me pulling with both hands on the pliers to get it out. The seal itself seems to have a steel belt in it to keep it stiff and was very very ridged.

With that and my new one in place in the lower i moved to to the upper half. i had my brass drift in hand and pressed hard.... noting.
using a small hammer on the drift... nothing..
i then loosend off the next two caps on the crank to try and give it a little room.. with some harder taps.... nothing.
all the time making sure i am on the seal and nothing else.
A bigger hammer... nothing then the brass drift bends in half,
An alloy drift and a good firm blow or 20 and nothing, neither end of the seal will move and both ends of he seal are now are a little deformed. that sucker is just not moving!!
:flamemad:

Right its been nearly six and a half hours, i am head to foot in grease and getting a little frustrated. i rtv up the edges of the seal where i have been pounding it and spend the next 60 min putting it all back together so i could get Jeep out of the garage before my wife got home.

In short i would just love to know what went wrong, I took my time, did not get upset (until the end) and there was not way that seal was going to move. needless to say it still leaks like bugger so i am really stuck as to what to do next, Pull the motor?

ANY advice you have would be appreciated.

Dave

I think I read on some threads that sometimes they are easier if the tranns is out, and flexplate/flywheel is removed, but Im not sure why. This would also be alot more work. You might try to loosening the #5 and #4 crank bearings to hopefully lower the crankshaft loosening up the rear, but Im not sure that would work if you are having that much trouble with it to begin with. the two that I have done took a hand push with a punch to loosen, and they slid right out. good luck

I had the exact same issue with my '88 Comanche. The oil pan gasket acted more like a cement than a gasket, not allowing the pan to separate from the block. The top half of the rear main seal also did not move AT ALL and I mashed up the ends so bad using various methods - brass drift, steel punch, AIR HAMMER! What I eventually had to do was loosen ALL of the main bolts and caps and I let the crank drop down about a 3/16" or so. I then went back to the rear main seal with the steel punch and it came out after a few good taps.

The bad news is that the rear still leaks. The crankshaft was kind of galled up where the seal rides (the old seal was ROCK hard) so I'm thinking there is just no way any seal is going to work with the condition of the crank. The leak did slow down some to maybe 3-4 drops after shutdown rather than the 10-15 before

Thanks for the info. I did the 2 caps next to the main that was removing and it did not seem to help. I think I'll take a deep breath in a few weeks when i back from my next work trip, Drop the xfer case and the trans, then the pan again and then drop that crank as you describe Terra.
once mine was hot i was getting about a drop every 2 seconds on the drive at idel so its just not drivable like that.

On a side note i could see i had a little play in the piston rods at the crank end on all the pistons, is this normal? I have never rebuilt an engine so have no idea of the tolerances.

Thanks
Dave

I had a very similar problem getting the top of the rear seal out. I pounded for an hour with my brass punch and a hammer. Finally I wised up and used a mallet instead of a hammer to whack the punch. After 2-3 blows the seal was protruding far enough for me to get the pliers on it. I'm not sure it that advise will help at all. All I know is that it worked for me. Also, my oil pan was also a huge pain in the butt to get out. I think my control arms were limiting the downward travel of my axle. Between all those problems and painting my pan it took a good 4 evenings after work for me to get the job done.

http://naxja.org/forum/showthread.php?t=1003218

i dont knw if you read my thread or not, but i ran into every problem you did. you have to hit the upper seal left side, then right side. hit it a few times then move to the other side. use a brass drift and large mual if you have too. its a bitch, and you should have seen my pan, the PO used silicon on both sides of the gasket.( it took two hours of scraping. a wire wheel would have been nice. i actually broke off a piece of my block when i did mine, hope u dont do the same. good luck

I had the same problem getting the pan off my 87. No matter how far down I pulled the axle and how far up I jacked the body, it was no go with axle in until I took the oil pump out from the side.

Sorry I can't help with the seal. Mine came right out. After reinstallation it leaked like crazy for a while, then stopped. I think it was the pan gasket, but I was never sure. I gave the Jeep to my daughter, told her to keep a case of oil in the back and always run it at a quart down, and after a couple of cases it just stopped leaking.

If you run stock LCA's, you won't get enough droop, due to the arms binding on the axle bracket.
Just pulled mine today and ran into that. What I did was unbolt one LCA (passenger side on mine), this allowed enough droop to remove the paqn to the rear.
I did this mainly to replace the pump with a new HV and do the rear main seal.
Pulling a rod cap off, however, found only copper.
New rod and main bearings on the way-should have awesome oil pressure when this is done.

Nick