4.0 rear main seal that worked

[1986goose]

I gave some guy $200 to remove the motor from his 88 XJ so I could put it in my 86 MJ. Took me a few weekends but I got the POS 2.5l and ax-5 outta there and mounted the 4.0 with only minor massages to the firewall. Started up as soon as I plugged the harness in and hooked up the fuel lines. 
 

Only problem is that it leaked - from everywhere. Valve cover and oil filter jobs were easy. I knew it was the rear main bc what else ya know it was a $200 motor.
 

First try - new rear main seal and oil pan gasket. Drained the oil and took it all apart. The old rear main was cracked and damn near seized inside the bearing cap. Got it out, blasted with brake clean and brass brush, autozone silicone only where specified by installation manual. Let dry for 48 hours. Leaking again immediately. 
 

Second try - new rear main but reused the blue fel-pro oil pan gasket cause I’m cheap. Did some digging and some people said they had success with anaerobic gasket maker (the kind that makes a plastic seal when torqued between two steel faces). Went a little crazy and put it on the entire bearing cap face. Let cure for a week. Leaking again - probably worse. 
 

Third try - I work construction and saw that one of my vendors had sent too many tubes of this industrial blue loctite silicone gasket maker. Why not try it? New oil pan gasket, new rear main. Spent extra time cleaning each and every with razor blade and brass brush and used lots of brake clean. Squeezed this blue stuff up into the bearing cap on each side, stuck the upper piece in, more blue stuff in the seat of the lower bearing cap, more blue stuff on the face all around the cap, and a 1/8” bead of it on top and bottom of the new oil pan gasket. It’s actually the same color as the blue fel-pro gasket. Let cure for a week. No leaks. Use this stuff. 

[Eagle_SX4]

3 hours ago, 1986goose said:

Second try - new rear main but reused the blue fel-pro oil pan gasket cause I’m cheap.

It is probably not your rear main seal. I had this exact thing happen when I did mine. What is probably happening is your oil pan gasket is not seated properly under the rear main cap. The blue fel-pro gasket likes to push in or out of the oil pan and leak every where once the oil is moving inside the engine. I used some silicone to glue the gasket to the oil pan (just under the rear main seal) and then put it back together and has been fine since.