312 rear main seal

Yes, if you can get the pan off. You may need to drop the drag link. Also may need to rotate the crank to get the counterweights up out of the way of the pan unless you're really lucky.
 
I replaced the rear main on my 312 with the engine in place in my roadster. I used the Best Garket black neoprene seal, and followed the instructions by Ted Eaton. One caution, Best made some silicone seals that were orange, and they failed often under 500 miles. That's what I replaced. If you get one (and you shouldn't, they should all be gone) don't use it.

Ted's article

http://www.eatonbalancing.com/2008/09/10/neoprene-rear-seal-installation-for-the-y-and-others/
 
cavecreekjake said:
Can the rear main seal be replaced without pulling the engine?
Thanks
Click to expand...

Jake, my engine is probably 35 years since it had gaskets. I had several small leaks, enough to really upset me. I changed oil to mobile 1 and added 1 qt of Lucas stop leak, I also added a little of the transmission stop leak and a little power steering stop leak. That was a year ago and I drive the car often. Every now and then I see a drop. Getting oil leaks out of a 63 year old car is a task.
If the only leak you have is a rear main, then it would probably be a good idea to replace the rear seal.
Good luck

Wrong car, the car I was referring to, is a 1956 Ford Fairlane 292
 
Last edited:
If you still have the rope seal still you will need to get creative to remove it. Slightly loosen the main caps and make some little picks and needle nose pliers to remove. That's the hardest part. And as miker98038 stated use only the black colored "Best" Brand seal. I have found it best to slightly clock the new seal slightly when installing. Maybe 1/4-3/8" and either red silicone or Permatex "Right Stuff" on the cap mating surface. Silicone is okay as long as you aren't too messy. Clocking probably is not necessary but it helps seal the mating surface. Before installing the side rails put a little sealer in the groove first. The new seal should have a horn to help getting it started around the crank. I myself prefer Permatex.
 
I have seen more leaks at the holders mount than the actual seal. Make all the parts very clean, use lacquer thinner or acetone and Q Tips. The threads on the two bolts too. Use sealer very sparingly, but very accurately.
 
Ole Don said:
I have seen more leaks at the holders mount than the actual seal. Make all the parts very clean, use lacquer thinner or acetone and Q Tips. The threads on the two bolts too. Use sealer very sparingly, but very accurately.[/QUOTE

On a 312 don't rule out a cracked block either.
Click to expand...
 
This post is based on the assumption that where oil seal retainer meets the engine block contributes to leakage at the points of contact, between the block and the retainer this might not get a proper seal
. Would it help to cut the rope seal that goes in the block short and the rope seal that goes in the retainer long so the seam of the rope seal would higher than the contact points of the block and the retainer.
just a thought while I was assembling the engine. A person could put one part of contacts points on the seal staggered which might help slow down the leak.
Let me know what you think. Larry
 
Ted Eaton’s article I linked above discusses that, with pictures. Read it carefully and avoid most problems.
 
You must log in or register to reply here.
Back
Top