Remove the disc pads and disconnect the brake flexible hose from the rigid brake line at the support bracket, capping the line to prevent fluid loss. Unbolt and remove the caliper along with the flexible hose, noting the copper sealing gaskets that should be replaced upon reconnection. Clean the exterior of the caliper with brake fluid, avoiding gasoline or solvents, and place the assembly on a clean workbench. Drain the fluid from the caliper, then insert a cloth pad between the caliper piston and body. Apply air pressure to the fluid inlet hole to free the piston; if unsuccessful, use hydraulic fluid pressure by reconnecting the caliper to the brake line and having an assistant slowly depress the brake pedal to force the piston out. Carefully pry the dust boot out of the caliper bore and remove the piston seal using a small piece of wood or plastic to avoid damage. Remove the caliper bleeder valve and discard the sleeves, bushings, and all rubber parts. Clean the remaining components in brake fluid, allowing them to drain and shaking them to remove excess fluid. Examine the piston for defects and check the caliper bore, allowing light polishing for minor corrosion. Lubricate the piston bores and seal with clean brake fluid, positioning the seal in the groove. Lubricate the piston and assemble a new boot with the fold towards the open end, then insert the piston squarely into the caliper bore and apply force to seat it. Position the dust boot in the caliper counter bore and use a suitable drift to secure it, ensuring even installation. Install the bleeder screw and complete the installation by reversing the removal steps, using new copper gaskets for the brake hose connection and bleeding the system of air.