I have decided to rebuild my calipers instead of turning them in for cores and getting the rebuilts. After going through the battle of getting the pistons out. I been soaking the parts in Evapo-Rust. It seems to clean them up pretty good The condition of the piston varied from pitted to very clean. I'm planning on replacing the pistons with ones from Rock Auto and also buying the seal kit from them. A question that I have is. What should I paint the bare castings with? Also, it look like the groove the boot goes into is a prone area for rust. I'm thinking that that you would want to get some kind of protective coating into the first groove. Any advice or opinions?