59-82 Rear Main Seal

[Wayne L.]

Paragon's catalog lists two different rear main seals for 59-82, one narrow type, and one wide type. Other than width, can either one be used, and which is best?
Can the rear main seals be changed with the engine in the car?
Thanks, Wayne 4921

[Jim T.]

Re: 59-82 Rear Main Seal

Yes the rear main seal can be changed with the engine in the car.

[Joe L.]

Re: 59-82 Rear Main Seal

Wayne-----

GM has used several successive rear main seals over the 1959 to 1986 period. There may have been some design difference with respect to "narrow" and "wide", although GM never specified a "1st design" or "2nd design" at any time with respect to the neoprene seals. I've never been able to "pin down" or confirm if there were actual differences in the configuration of the GM seals used over the years.

Although never available from GM, there are also available in the aftermarket seals with different lip locations. This is done to relocate the lip on the crankshaft journal so that a grooved, worn area can be "by-passed" and a fresh seal surface utilized. This may be what the Paragon reference to "narrow" and "wide" refers to.

At the present time, only 1 seal is available from GM for all 1959-86 small blocks. If your crankshaft rear seal journal is in good condtion with no wear or grooving, then I recommend that you use seal GM #10121044 or Fel-Pro #2909. These are an expensive seal and are manufactured from an extremely durable, high performance fluroelastomer. The GM version list for about 36 bucks and the Fel-Pro will cost about 20 bucks in most auto parts stores. However, they are the best available seal for neoprene seal type engines. For a rear main seal, YOU WANT THE BEST AVAILABLE SEAL.

If your crankshaft rear main seal journal is grooved due to seal-induced wear, then you'll need to use one of the aftermarket seals with the relocated seal lip. No such seal is now or ever was available from GM.

[Wayne L.]

Re: 59-82 Rear Main Seal

Jim-any tricks, or special tools? Thanks, Wayne

[Wayne L.]

Re: 59-82 Rear Main Seal

Joe-thanks for all the info-a big help. Wayne