Make sure parking brake is released as well if for some reason you applied it and man handled the caliper off. (I've seen it done before) and they can be rather tough to get to budge with age and miles. Like stated above you must rotate the piston while compressing it. The disk brake piston cube you can get at an auto store works well enough on our cars if you needing a cheap option
Thank you gents. This is all previously unknown information. I did manhandle the left rear and now the wheel seems locked up. The parking brake cable appears to be in the same position at the caliper but maybe I will pull the lever and release it again?
Ty! Now on to the rear springs. Took the car to Tuffys to see if they could shim the messed up alignment in the rear. Found a broken spring on left side. Could that be why both rear tires are wearing the frick out in 6-8 months or so?? Lol