I take my master and wheel cylinders down to a local machine shop. They let me watch as they use a Sunnen hone on them. They take .004" to 010" out of them for around $4-$10 each. If there are still pits in them, it depends on where the pits are. If in the center of the cylinder it can be OK. If it is where the puc seal rides, then it isn't. I put a new kit in them and they work great. I don't let them run a ball hone in them afterward either. Staight off the hone and then brake clean. Lube them up with brake fluid when assembled.
