RMK01GT

if its stuck it has to be misaligned (not straight in the cylinder bore)
look at it real close, square the piston up to the cylinder (using a c-clamp to straighten it back out, or percision hammer work like mentioned above) then you should be able to hook your brake line back up and push the piston out with the brake pedal

EDIT: I looked at the picture you posted and you would have to install the missing piston for that to work lol

trailor

yeah well the hammer and chisel bit really messed up the lip around the piston, probably not a good sign for that piston either way. thanks for the input, but I have two new calipers coming in today or tomorrow and have to return the old ones for a $60 credit, so no point in fooling with them. however, to the next person who wants to try rebuilding rather than replacing, i'm sure your advice will be rather useful!