My master cylinder drips at the front boot. It has a 1 1/8" bore. I rebuilt it with part 72-256 from classicparts.com. Drip continued. Tried a 1 1/4" kit, but it doesn't fit... clearly a 1 1/8" bore.

I bled the brakes after both rebuilds.

What can I try next?
What am I missing?

The reservoir drains in 24 hours one drip at a time.

Last edited by Justhorsenround; 04/06/2020 3:57 PM. Reason: Spelling

1952 Chevy 3100 with GM Straight 6 250 engine