Thanks, Chris! I grabbed Lycoming SI 1324 version A off the Internet which recommended the Pliobond 20. Thanks for dragging me into the 21st century! I'm now wondering if the red Silastic 736 wouldn't work better than the clear Silastic 737. The red RTV is used to seal automobile water pump tubing, for example. Engineers! Always trying to re-design stuff! LOL!

Rubber will last much longer if submerged in oil.  The failure may simply be due to nothing more than the years of sitting idle.

In terms of the seal installation, I would recommend using Dow Corning 737 (see SI 1324C, 2009), Pliobond is offered up as an alternative if the 737 is not available.  After having recently changed a shaft seal, I highly recommend sticking with the 737, in particular for the do-it-yourselfer.  It provides much more working time and is easier to handle than contact adhesive.  I can see many A&Ps not wanting to use it because of the longer cure time (24 hours).

Chris Zavatson