B Engine rear main seal leak repair options.

[bherman]

Hello All, recently I started and performed the break-in process on the "new" engine for my project car. Unfortunately I have a rear main seal leak. I'm trying to determine if it's possible to replace the seal in the car and without dropping the crank. I've been told this can be done successfully but I have no idea if this is a real possibility or just a waste of time. I would appreciate your thoughts and opinions, thanks, Brian.

Hi Guys' first of all thank you all for your ideas and tips! As some of you suggested it was not leaking at the rear seal, but at the side seals on the retainer/holder. When we installed the pan originally, we used Hylomar instead of silicone. When I pulled the pan the first time it appeared that there was a leak path on the pan rail at the joints for the side seals on the holder/retainer. We installed a new gasket and used silicone for sealer. When I removed the pan the second time (it still leaked) one of the side seals came down with the pan.....an ah ha moment. We removed the seal holder and started inspecting and measuring. I suspected that the side seals were the likely suspects, but decided to inspect the upper half of the seal before we re-assembled it (mostly because I just love scraping gaskets and cleaning pan and block rails). The seal was made of Viton and I couldn't find any new ones in anything but the standard material (black). The seal looked perfect, so we reused it. We measured the opening in the block where the side seals contact and it measured 5.143". In addition the finish on the sides were somewhat rough, I think probably from shot cleaning. The original billet seal holder (flat seal style) measured 5.168" on the outside of the seal strips. Not much compression for 4 sealing surfaces especially when the block isn't pristine. I purchased a new style seal holder (o-ring style) and it measured 5.194" across the o-rings. The increased compression and improved retention of the side seal (o-ring), which allows a thin wipe of sealer on the block resolved the problem.

Thanks again for your thoughts and suggestions, Brian.