I replaced the rear disc brake pads on my chevy 1500 and took it for a short test run. when I got out of the truck I smelled hot breaks, the rotors were both hotter n hades and the pads were too, I waited a while for them to cool and took them back apart, both calipers were still pressing the pads tight against the rotors, I Had to knock them back off with a hammer, I put the ole C clamp on the pistons and pushed them back in, Inspected all my work and and reassembled. took it back for a quick spin and its doing the same thing. Why would both be doing this?