In some cases the replacement pads are thicker than the originals with the logic being that the rotors are thinner with age, this is rare. The pistons should go back into place now that the suppy line has been removed. Try pressing them back into the caliper with a c-clamp one at a time. To get the bleeder out, apply penitrating oil, tap on the open end with a hammer and then using a good pair of vise grips try breaking it loose and then work it in and out to clean the threads as you go. Any good auto parts store can suppy you with a new bleeder screw
randall
March 2008