Image of flywheel side

How to Cure Leaking Rear Main Seals

“Grumpy” Jenkins, a prominent drag racer from the 60’s and 70’s, came up with a homemade fix for rear main leaks that really works. Whether you pull the pan to fix a leaky rear main or you’re building a motor with a two piece R main seal, this mod is a MUST.

  • With the bearing inserted in its position in the ”lower” rear main cap for support, gently clamp in a vise and cut 2 diagonal grooves away from the seal.
  • Use a small diameter cutoff disc (See picture). This takes pressure away from squirting at the seal.
  • Remove just enough material to allow the oil to escape into the pan (See picture) and of course always stagger the main seals part line in relation to the main caps part line.

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