Just pry them back in with a screw driver or something like that. Do one pad at a time and hold the other piston at you compress the mate. As you press in on one piston, the other will want to extend and can actually come out too far. Very simple process.
ok I didn't know if that would be enough pressure. I know there is no way my PBR's would go back that easy. It was hard enough with a c-clamp. Boy am I glad to gid rid of those things. thanks for the input.
I pull one pad out and stick two wrenches (one between each piston and the rotor) and push with them. It works best for me to use the closed end of a combination wrench 3/4" or larger. Once I get the two pressed back, I insert a new pad and then remove the pad on the other side and repeat process.