Started tinkering yesterday. The original master cylinder was leaking badly at the rear seal by the booster. Brake fluid was running down onto the subframe. Luckily I still had the reproduction master cylinder left over from the black 72. So I installed that one as a stuntman for the original one while I send this one out to Whitepost.
From sitting for 40 years with the same brake fluid, the bottom of the reservoir was filled to about 1/4 inch with rusty colored goo. It was a bear to get the inner far piston out. That same rusty goo was in the bore area as well and not only pitted the bore but devoured the valve itself:
You can see that these master cylinders were painted a flat black originally. Not a lot of the paint remains but it is there in places.
Here is the reproduction bleeder style master cylinder in place with the original cap and bail on it.
