If the parking brake uses this caliper then it is threaded a special tool (not expensive available at Sear or auto parts) is required to twist it back into the caliper body they have parking brake shoesd wich are cable drive,,,,,,, the caliper is stationary use a screw driver
Most likely the piston will need to be turned not compressed
Use a C clamp to push the piston out of the way to remove and also to place back on rotor.
I have used a large "C" clamp, to compress the caliper flush to the face.
Rewind it with a piston rewind tool or, at a pinch, use needle nose pliers.
Replace the caliper and bleed the brake system.
You will need a caliper rewinding tool
How do you compress the rear brake caliper pistons to install new pads on vw polo 08 model?Read more: How_do_you_compress_the_rear_brake_caliper_pistons_to_install_new_pads_on_vw_polo_08_model
It requires a special tool to turn and compress the piston in at the same time.
Get a 4 Inch C Clamp Leave the Pad In The Caliper On The Plunger Side Open The Clamp Wide enough To Clamp on The Back Of Caliper and Pad. It should Easily compress. However, as these are rear disc, the emergency brake is connected as well. A C clamp will not work in this situation because the piston caliper is threaded and has to be retracted by turning the piston caliper with a special tool that can be gotten at most auto parts for around 10-15 dollars. Make sure the cap is off the master cylinder reservoir. Not difficult.
You need a caliper tool and a ratchet. Caliper tool is a cube with prongs on it, a couple dollars at a parts store or online. Just turn the caliper tool and on the caliper and it will compress.
c clamp or channel locks or depress the pedal
with a large pear of channel locks,or a caliper compressor