You should install the bleeder valve and the bleeder valve cap to the caliper housing, install a new lubricated piston seal to the caliper bore grooves, ensure that the piston seal is not twisted, install the lubricated boot onto the
Brake Caliper piston, lubricate the brake caliper piston with clean brake fluid, install the brake caliper piston and the brake caliper piston boot into the bore of the caliper, push the brake caliper piston to the bottom of the bore, seat the caliper boot in the caliper housing counterbore and install the caliper.