Oldsmobile/Buick Repair: 94 Buick Regal Rear Disk Brakes, caliper piston, disk brakes

Question
I am trying to change the rear disk brakes on my 94 Buick Regal Custom. (3.8 V-6) I have done this several times on other vehicles and have never had so much trouble compressing the caliper piston so the new pads will fit. I have tried a "C" clamp and neither side will budge. I have been told that some vehicles calipers have to be turned to get them to go back in, tried this and the piston turns but does not move in. This vehicle has ABS. Is there something I need to do the ABS system? Any help would be appreciated!

Answer
hi roy. no do nothing with abs.here is the trick.use a c clamp.keep pressure hold the clamp and turn the caliper .you must keep pressure on the piston as you turn.very tricky.if this don,t work remove bleeders while useing this method.if neither works calipers are frozen and need replaced.good luck billymac please rate my help