On the rear brakes I know you are supposed to screw them in to make them go back but, how far do the screw in? Is it till it stops? Till it’s flush with the caliper? Mine turns very easily but it doesn’t seem like it’s going back any.
First make sure the brake fluid reservoir is not full so you have head room for the fluid you move back when turning the Pistons back in. Turn and push at the same time and screw them in until flush with the calliper body.