some leaks are the pan gasket and seal retainer. i find the best gaskets are way better  for leaks in the rear seal aria oil will drip and appear to be the rear seal

NOS rope seals were likely then made with asbestos. While it has been banned for health reasons there isn't really any viable substitute. The modern replacement "green" rope type seals don't work very well. So, the Neoprene type seems to be the practical work around.

back in the 70s all i ever used were rope seals 289s 390 never had a leak.the first y blocks i rebuilt i used rope and never had any leaks on any engine.to this day if i could buy good rope seals i would use them.i trust them over the rubber seals.ive taken apart 56 engines with close to 100,000 on them original motors that were not leaking.back when an easy fix for leaking seals was to force a steel shim over the top half and just replace the bottom half.not many had the tool for doing this.i would like to see a picture of one.

Yes I am aware its an old Post. I was reviewing every Post related to rear main Leaks. There's about 25+ over the Years. They start  on Page 100 of the old Topics. I was not aware He is not on anymore. Just trying to get a Consensus of alternative fix's for Leak.

  

Permatex^® The Right Stuff^® Gasket Maker

- https://www.permatex.com/product-category/gasketing/the-right-stuff-gasket-makers/

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Oldcarmark:  Are you aware you're replying to a 5 yr old posting?  In any case, lyonroad (aka Mark also) has withdrawn from this site some time ago. He's somewhat known to me personally, but I won't comment on his withdrawal from this site.. 


Paul

Did You find that filling the Sides instead of using Side Seals was successful? No Leaks even now Years later?

  

Thanks! Have you tried your Motor with this "fix"?

  

Mark, I've seen it at a lot of the parts stores. It is usually in the Permatex section, and its not cheap. Sometimes it comes in a kit of two cartridges and a small calking gun. I found a single tube and use a regular calking gun. I used neoprene type seals and followed Ted's procedure as best as I could.

Mark

1956 Mercury M100
1955 Ford Fairlane Club Sedan
Delta, British Columbia

Do rear main seals usually leak from the bottom half of the seal or top?Or is it 50/50?