There are a few machine shops that rehab old brake cylinders, both master and wheel type, by boring the casting out and installing a stainless steel sleeve. Then when the cylinder is rebuilt, rust pitting becomes a non-issue- - - - -better than new!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!