Master cyclender question.

The other problem with rebuilt MC's is that when they hone the cylinder, it can leave sharp edges at the ports that tear the piston seal, at least that happened in my 65 Newport with a fairly new MC.

It is cheap to rebuild a whole drum brake system and within most shade-trees abilities. Just follow a manual and don't Billy-Bob anything. New wheel cylinders are often $6, so no sense rebuilding. If you don't want rusty internals and ruined paint, you can use silicone fluid. I do, as does the U.S. military, but many on FABO imagine problems.