Most times just a clamp will push it back in but if it gives too much trouble you may need to loosen the bleeder. Some rear pistons for disk brakes need to be turned back in and a special tool is available for the job at your local parts store.
Try bleeding your brake lines, you may have some gunk in there.
The caliper piston may not retract properly due to a lack of lubrication, a damaged seal, or air trapped in the brake system.
The Brake Piston Cube is a cube-shaped tool used to retract brake caliper pistons in vehicles when changing brake pads. Its design allows it to fit into the caliper housing and apply even pressure to retract the pistons back into the caliper, facilitating easier brake pad replacement. By turning the Brake Piston Cube, the pistons are compressed uniformly without damaging the caliper or seals.
The piston is not stuck. It must be rotated to retract it. There are two depressions on the piston face. Use a pair of needle nose pliars to turn the piston clockwise to retract it. Turn it until the face of the piston is flush with the boot.
You cant, it needs a 'C' clamp.
Compressing the rear brake caliper piston on a 2008 Chrysler Town and Country requires a special tool that pushes in and turns the piston at the same time.
It helps re-fit to slide it back a fraction.
a special scanner called a v.a.g. has to be used to retract the electronic e brake system, and will also retract caliper piston..DO NOT TRY WITH OUT TOOL !!!!!
If it is the front brake use a "C" clamp to retract piston If it is the rear and the parking brake is used by this caliper piston is threaded and a special tool (not expensive) available at Sears or auto parts to "screw" piston into caliper body
Clockwise to retract piston into caliper body
The brake caliper may not retract properly due to issues such as a stuck piston, worn out seals, or debris buildup. These issues can prevent the caliper from releasing pressure on the brake pads, leading to brake drag and reduced braking performance.
You need to turn (screw, rotate) the piston clockwise in the caliper a large number of times to make it fully retract. You can insert some kind of tool into the indentations in the face of the piston, or grip the very top edge of the piston with pliers in order to turn it. It has to be fully retracted to allow enough space for "new" pads to be installed.