[eapcpa]

Very likely that the caliper needs to be rebuilt and you need to check the piston for pitting. Brake fluid absorbs moisture over time which causes corrosion inside the system. When enough corrosion builds up it gets stuck in the caliper bore and will not retract when you release the pedal. We are talking fractions of an inch. Annual flushing of the fluid helps prevent the corrosion. If the piston has any pitting that is present after buffing with emory cloth or similar ultra fine sandpaper (1500 grit) the piston needs to be replaced. Only the outside surface needs to be smooth where it contacts the caliper seal but if you are taking it out clean it up. Rebuild both while you are doing it and replace all of the fluid with quality stuff. Good luck.