You can't unsieze the piston with a G-clamp, and it won't budge if you try anyway. They're wound in on a screw thread which exists to take up any slack for the handbrake to work as the pads wear. You need to wind them with a special tool, although a large pair of grips on the 1/16" of exposed metal beside the gater will work also.
The handbrake can be siezed for a number of different reasons, the main culprits being the lever on the caliper which needs regular re-greasing, or the handbrake cable itself, which is a very poor design having a plastic sheathe which wears and eventually snags the cable.
The caliper probably isn't siezed at all.
|