Rear Main Seal is a bugger!

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edognight
Posts: 48
Joined: Tue Jun 13, 2017 2:32 pm

Rear Main Seal is a bugger!

Post by edognight »

1983 jeep waggy, automatic. Runs good, leaked oil about a drop a second. It has been my experience with this jeep that every plastic part that touched gas or oil is bad.

So, I pulled the pan, loosned all the main caps, the belts on the pulley, and got the old seal out. The top was an issue, but I made a tool, like a long punch and that did it. It was hard to get out, so it makes sense that the new one WILL NOT GO IN!

all main caps are wiggling loose. accessory belts are loose, I have tried to force in three upper seals and every one tears. one about 1/3 way in and two about 2/3 way in, i tried soap on the outside, oil on the inside, vaseline, and just soap, nothing works. It is just too tight between the crank and the block. even with prying on the crank to force it down with a pry bar. the crank will not be moved at all.

So, the only idea I can come up with is either try a rope seal, or loosen the transmission bolts which should allow the crank to be dropped down a little. Other than that, I am stumped. Any help appreciated.
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REDONE
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Location: Lakewood and Bailey, CO

Re: Rear Main Seal is a bugger!

Post by REDONE »

They suck, what can I say. I loosen the Caps (barely)and leave the rear cap off, slather it with oil, then I rotate the crank to help pull it through, but I've only done it once that way. Worked for me that one time though.
You might have a lump of crud in the seal groove that's hanging you up.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.
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Tatsadasayago
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Location: Sacramento, CA

Re: Rear Main Seal is a bugger!

Post by Tatsadasayago »

Sometimes, loosening the transmission bell housing bolts creates just enough slack to allow the seal to go in without damaging it.
1977 Cherokee Chief - The Blair Jeep Project III
A collection of parts flying in close formation

Topic author
edognight
Posts: 48
Joined: Tue Jun 13, 2017 2:32 pm

Re: Rear Main Seal is a bugger!

Post by edognight »

Question. has anyone tried clamping the seal in the bearing cap overnight to squish it, the quickly lubing it up and shoving it through before the plastic reforms??

SJTD
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Location: Lompoc, Sunland or somewhere between

Re: Rear Main Seal is a bugger!

Post by SJTD »

Maybe heat it up so itsa more flexible?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

FSJ Guy
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Re: Rear Main Seal is a bugger!

Post by FSJ Guy »

Weird. I've never had that much trouble with a RMS. Maybe stick it in near boiling hot water before trying to install it? Not sure where you're located in the world, but in many parts of the USA, it's COLD now. So if it's too cold, the rubber may not be as flexible as it is when it's 75F and sunny out.
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!

Topic author
edognight
Posts: 48
Joined: Tue Jun 13, 2017 2:32 pm

Re: Rear Main Seal is a bugger!

Post by edognight »

Guys, thanks for the affirmations, I am going to keep at it, but I thonk I am doing something wrong, because this thisng WILL NOT be slid into place. I am 0/3 on them, just ordered two more, but I am trying another brand this time...
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REDONE
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Location: Lakewood and Bailey, CO

Re: Rear Main Seal is a bugger!

Post by REDONE »

Definitely keep at it! So many of us have done it that you know you can do it too. Thinking back, I'm pretty sure I lubed the seal with WD-40, not motor oil. Just a big sloppy spray with the straw all through the seal groove in the bock. I didn't loosen the other caps all that much in fact it probably wasn't enough to do anything, and I had the spark plugs out so it was really easy to turn the crank to help the seal along. No breaker bar or anything, I was just grabbing it by the counterweights and spinning it by hand while also feeding the seal with my fingers about an 1/8 inch at a time. Pinching it right next to the block, pushing down against the crank while also pushing it into the groove. It may sound tedious, but it was only about 1-2 minutes to get the seal all the way through. Good luck, buddy!
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.

SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Rear Main Seal is a bugger!

Post by SJTD »

Never done one of these. Is there room to put a piece of string through the back of the seal you could pull on to help keep it curved against the crank as you push?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.
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tgreese
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Re: Rear Main Seal is a bugger!

Post by tgreese »

There is a tool, often called a "sneaky pete" https://www.amazon.com/Lisle-27000-Snea ... B0002SRCJW but it's more meant for installing the rope seals than the neoprene seals. The neoprene seal is already half-circle shaped, and is supposed to be rigid enough to be pushed through the seal groove.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
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candymancan
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Re: Rear Main Seal is a bugger!

Post by candymancan »

I lnow ill be of no help.. I did my rear main seal a few months back as it was pissing oil out.. start it cold and within 5 min there was a massive puddle under it.

I could not get the upper seal out.. tried punches and so forth.. so rather then nick my crank shaft and damage the seal that wouldnt budge.. I decided to judt replace the lower half and cross my fingers.. Thankfully i got lucky and it stopped leaking.

Now i gatta tackle the intake manifold next spring.. It leaks so much oil out the back it covers the block side to side.


Fyi people habe recomend you use soap on the upper seal. Soap is a lot more slippery then engine oil.. So id try some thick slippery soap.. Not the cheap stuff but the liquid soap that super concentrated and thick.. Ive seen people do this before and it worked.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

csuengr
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Location: Sterling, CO

Re: Rear Main Seal is a bugger!

Post by csuengr »

Just be glad it isn't a one piece seal.
1977 Cherokee S, Ford 5.0, 5 speed, BW 1356, 33 x 10.50 BFG's. No longer my DD.
2007 Mercury Milan, 2.3L, 5-speed, now my DD. 29 mpg average.

SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Rear Main Seal is a bugger!

Post by SJTD »

But if it was a one piece seal he'd have bit the bullet, pulled the trans and been done!
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

Topic author
edognight
Posts: 48
Joined: Tue Jun 13, 2017 2:32 pm

Re: Rear Main Seal is a bugger!

Post by edognight »

So, I did it, much the same that 'Redone' above described it...i used a breaker bar, to turn the crank over while I pushed it in a little at a time. I did soak the seal in hot water, and this seemed to help alot. I also used vaseline, insert adult joke here__________.

Now it leaks the same or even worse. So I mught have messed up the pan install, but that is nowhere near as hard as the rear seal, and the rear main cap. Now I am off to do some research about what leaks out the back of the engine and on to the y pipe, the car smokes so bad, I can't drive it, but it is a project, and still fun, but very difficult to get to quit leaking oil.

Sometimes I fantasize about meeting a jeep engineer, and punching him out.
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REDONE
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Location: Lakewood and Bailey, CO

Re: Rear Main Seal is a bugger!

Post by REDONE »

One of the engineers is a member here. Don't blame the man, blame the times, haha!

As far as oil barfing out the back of the engine where you can't see it, 99.9% if the time, it's the back of the intake manifold. The block has a ridge that's maybe 1/4 inch wide front and rear, and anything that sits on top of it to seal against the intake is taller than it is wide, which means any kind of pressure on the crank case blows it out. The front is easier to get a good seal because you can see it, but the back, you can't.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.

candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Rear Main Seal is a bugger!

Post by candymancan »

yea my intake manifold leaks oil and it leaks down my block and will drip. Need yo fix that next year spring. mine doesnt leak enough to cause big stains so ive been putting it on the backburner.

Also to keep the oil from dripping on the exhaust.. Go to lowes get some thin 22ga steel the thin stuff you can bend by hand. cut a big square peice with sheers and measure where the two lower bolts for the transmission inspection cover are. Then drill two holes in the plate you made and then remove the inspectimn plate bolts and bolt that plate up. Now bend the plate at an angle and this way any oil that drains from the block down will go on that plate and drip passed the exhaust pipe.

If you need a picture ill take one. I had the same problem when my rear main leaked itd go on the exhaust and make tons of smoke. That thin plate bolted to trans inspection cover solved it
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
edognight
Posts: 48
Joined: Tue Jun 13, 2017 2:32 pm

Re: Rear Main Seal is a bugger!

Post by edognight »

Update: a leak less grand waggy!
I I noticed this jeep was leaking oil from everywhere that it could leak oil, including puffing out the dipstick hole. Hmmmmm. What would cause an engine to leak oil from everywhere? Too much pressure! So, I changed the breather cap and pcv valve, and no oil leak at all from anywhere, so far. So that rms, was the hardest single part I have ever had to change, and it didn't even need it, but alls well that ends well.

To recap, the breather was clogged, and it caused the crankcase to build up pressure, and the engine was leaking oil from the rear seal, front seal, left valve cover, and dip stick hole, I just thought I would post this in case it helps someone. The breather cap was at Oreilleys, but I sprung for one of the chrome Mr Gasket jobbies, and I have a happy jeep.

Thanks for everyone's help.

FSJ Guy
Posts: 1763
Joined: Fri Mar 15, 2013 3:03 pm

Re: Rear Main Seal is a bugger!

Post by FSJ Guy »

And who says that chrome don't get you home?? LOL!!!!

Glad it's fixed!
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!
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