Rear main seal replacement information

KATOSAH

MEMBER
1968 FORD MUSTANG
51,000 MILES

I just rebuilt my 4.7L 289 out of a 1968 mustang and initial start/warm-up went smooth except my rear main seal doesn't seem to be holding. I don't own a engine or car lift and I was wondering is the a feasible way to replace the seal without pulling the engine? Can you loosen the main bearings and lower the crank enough to replace it? Or lower trans?

1 Reply

CARADIODOC

MECHANIC
33,867 POSTS

That should be a two-piece rear seal. There's a tool to remove the upper part. You remove the rear bearing cap, then thread what looks like a pick but it has a screw thread on the end, into the end of the rope seal. If you used a rubber lip seal, you should be able to grab the end with a small needle nose pliers. Having a helper turn the crank by hand while you pull on it may make the seal come out easier.

To run the new upper half in, the tool looks like a wire screen formed into a tube, with a single wire for pulling. You feed the wire into the slot, then pull it out the other side. As you continue to pull on it, it acts like a "Chinese finger" and pulls tighter to grab the seal and pull it through. Be sure to lube the new seal with oil.