I have honed pits out of hard-to-find wheel cylinders by going several thousandths oversize by mounting the wheel cylinder in a drill press vise and using a 3-stone hone with plenty of brake fluid as a lubricant. Then I machined new pistons to be a snug slip fit in the oversize bores. The rubber cups will accommodate a pretty generous oversize and still seal, as long as the pistons don't wobble in the bore. A big GMC I was reworking the front brakes on had two cylinders per drum, at a cost from NAPA of $96.00 each. Rubber wheel cylinder cups were about $3.00 each. That was several years ago, and the truck is still running and stopping with no leaks.
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!