The master cylinder lid is also leaking. I'll have to fab up second gasket so the lid is held on tighter.
Darren, I had the same problem on my '72. watch these rebuilt master cylinders. i don't know what happens to them but the
top part of the master cylinder wasn't perfectly flat. so brake fluid ran out the front and on to the frame below it. all the paint
was gone, I WAS PISSED! i wish i had known about the DOT5 brake fluid. no matter what i did it wouldn't seal up right. i had
to replace the master cylinder twice till i found a good one. tried altering the gasket and making the lid tighter, didn't work.
if you can, have it machined flat, maybe take off .005 to .010 to get it right. don't know if there's new MC's out there.