Pontiac Repair: rear brakes, gran prix 3, screw assembly

Question
Should I be able to use a C-clamp to back off the calipers?
1994, Gran Prix 3.1.   One caliper I had a problem backing off, so I thought I would try "cycling" it and stepped on the pedal several times.  This did extend the caliper, however it felt really "wiggly" when I went to inspect it.  Broken?  I hope not.

Answer
Hey David:

Bad news Yep it's broken. #1 you need a special tool to not only compress the caliper but to also turn the piston in at the same time. There is a ratchet screw inside that caliper that the parking brake is attached to. #2 never depress the brake pedal is there is nothing pressing against the caliper because you will/did over extend the claiper. If it's not leaking fluid you may just may luck out and get iot back into place but you may have exteneded it past that screw assembly. You can try pressing the caliper in again and turn the piston at the same time with a pair of channel locks and you may just luck out but I doubt it. Good luck none the less :)