leaking rear main seal 1971 455 engine

[teemeup]

i've been told that i need to replace the crankshaft in order to have the best chance of stopping the oil leak because of the type of seal used? anyone's experiences or knowledge is appreciated. thanks

[Sgt Art]

Replace the crankshaft? Why? Is it damaged? Chances are, it has the old rope type seals that were used on many Olds V-8 engines. They're okay for awhile, but do eventually leak. If you can jack the engine up (remove the two long bolts that hold the motor mounts to the frame and it might help to take the distributor cap off) then you may be able to remove the oil pan and proceed to change the seal without pulling the entire engine. Note on getting the oil pan off: You may have to rotate the crank a bit to get the front counter weights clear. It can be difficult. If you can get the oil pan off, then remove the rear main bearing cap, this is where the rear seal is located. The lower part of the old seal is easy to extract as it just pulls out of the groove it sits in while you hold the cap in you hand. The upper can be tougher. There is a tool called a Sneaky Pete (about $5) that will "grab" hold and allow you to pull the upper part of the seal out. Now, replacing is a snap. Don't use another rope seal, get the rear bearing seal for a Ford 460 engine which is the neoprene type (it's in two half moon pieces) roll the upper in, set the lower in the main cap a dot and I mean just a dot of black silicon on the ends of the lower and put the cap on. It's a good idea to offset the halfs so that they mate up in side the main cap groove and not at the parting line between the upper and lower parts.

If what I said has you totally confused, then go to a pro, this is not a job for a newbie, it's hard, aggrivating and a little dangerous. As far as replacing the crank goes, the only reason to do that is if it's damaged which I doubt if all you have is a leaky seal. More than likely, you were told, the engine had to be pulled and the crank removed, which is also isn't necessary. However, If I were going this far, I'd want the crank inspected, maybe polished if necessary and all rod and main bearings inspected or replaced. The parts don't cost all that much as the labor is most of the job. A new oil pump is only about $35 +/- also.