AMC 360 Rear main seal

[Anvil-3]

I replaced a dripping rear main seal twice now that’s worse than it was originally. It seems like there’s not a lot of options out there and a lot are out of spec. It’s totally stalled my progress as I’m getting tired of replacing the seal over and over for no reason.

Does anyone have a recommendation for a good brand or P/N that reliably seals?

(89 grand wagoneer - 360/727)


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[letank]

The only thing is that you may need a little more sealant on the corners, or may be it is your oil pan seal that is not doing its job because the bolts hole have been slightly deformed and the oil pan gasket cannot pick up the slack.

Add some dye, run the engine at idle for 1 or 2 min and see where the dye is more apparent.

The RMS I bought is usually from the big parts store and probably a Fel-Pro. I usually get 2 because sometimes the engine block is so sharp I had cut a sliver of the seal.

Otherwise your crankshaft could be wobbly, any fore and aft motion that is over 1/4" when you grasp the harmonic balancer with your hands and try to push/pull. That would be the thrust bearing going south, it can be fix by a weld and turned at a crankshaft repair place.

[tgreese]

Regarding brand, Fel-Pro is the industry standard. I see four brands here https://www.rockauto.com/en/catalog/jee ... +seal,5604 - Mahle and Victor are good and well-known brands, and possibly are the same part as the Fel-Pro. All are rubber. There's also the EngineTech seal - same price, but made of polyacrylate. They have a video for the polyacrylate part that may convince you - sorry, no personal experience. Kinda think any of these, properly installed, will work well.

Some engines can use a rope seal. These engines came with a two-piece rubber seal from the factory and cannot accept a rope seal.

The procedure is covered at page 9-175 of the '89 TSM. Free to read and download at the Tom COllins site. Suggest you review the procedure there and verify your methods.

[Stuka]

I have just used the Fel-Pro part.

The big key thing to do is to remove ALL oil from the surfaces the seal touches. Typically I use brake clean. If there is any oily residue, the seal won't seal, and any RTV used won't seal either.

[Srdayflyer]

are you using felpros removable oil pan support pins,they screw into the oil pan bolt holes allows you to have the oil pan just supported enough to start all the bolts except the 6 support pins which you remove ,then you can tighten the pan without having to do a balancing act, and allows 1 man (easy ) install. ive used these on several oil seal replacement jobs best 10 bucks ive ever spent, got questions i can get you the p/n

[Anvil-3]

I have just used the Fel-Pro part.

The big key thing to do is to remove ALL oil from the surfaces the seal touches. Typically I use brake clean. If there is any oily residue, the seal won't seal, and any RTV used won't seal either.

Mm that is likely the issue on the rear main. I have all new felpro rear seals to install and will do that. Regarding the pan I finally got a new pan that should solve that leak, I think the sealing surface is just too warped to seal well


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[Anvil-3]

For those interested, I got a new pan and cleaned and reinstalled the rear main seal. Seems to have fixed everything, the new pan in much much tighter at front and rear than the old one. So much better. Thanks for the help everyone


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[Greg72]

For those interested, I got a new pan and cleaned and reinstalled the rear main seal. Seems to have fixed everything, the new pan in much much tighter at front and rear than the old one. So much better. Thanks for the help everyone


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Congrats!!!

Just out of curiosity... were you able to do the rear main by pulling the oilpan only....or did you have to pull the entire engine? I've got a leak back there somewhere on my '89 (either valve cover gaskets or rear main... but probably rear main) and I've been avoiding it completely thinking that the entire engine had to come out.

How difficult of a job did it turn out to be.... ?


-G

[Anvil-3]

For those interested, I got a new pan and cleaned and reinstalled the rear main seal. Seems to have fixed everything, the new pan in much much tighter at front and rear than the old one. So much better. Thanks for the help everyone


Sent from my iPhone using Tapatalk

Congrats!!!

Just out of curiosity... were you able to do the rear main by pulling the oilpan only....or did you have to pull the entire engine? I've got a leak back there somewhere on my '89 (either valve cover gaskets or rear main... but probably rear main) and I've been avoiding it completely thinking that the entire engine had to come out.

How difficult of a job did it turn out to be.... ?


-G

Pulling the rear main required me to pull a section of exhaust (collector?) and the oil pan and rear bearing cap. It’s a 2 piece seal so no need to pull the engine. Through my difficulties I spent more time on oil pan bolts than anything. Definitely wouldn’t pull the engine unless you have other major issues to contend with


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