To service and repair the rear brake caliper (25/35 series), begin with safety precautions by keeping in mind the irritants of brake dust and brake fluids. First of all, disassemble the brake caliper properly and without using mineral oil substances on a clean bench and remove it off the vehicle. Be alert not to get hurt when using compressed air insert a thin piece of wood in front of the
Pistons in order to avoid breakage while taking off pistons directing compressed air to the inlet fitting port of the brake hose. Take out the pistons, piston boots, and Piston seals, and then the brake caliper bleed screw and the cap that covers it. Check the brake caliper bores and Piston seal groove spots for seating for too much wear and be sure to retrieve the brake caliper housing if necessary as well as the mounting bracket for wear if it necessitates a replacement. After withdrawing from the brake pad guidance surfaces and components not included in the repair kit, wash all the residues with denatured alcohol before drying using non-lubricated filtered compressed air to ensure the passages are clear. To assemble install the brake caliper bleed screw tightening it to 12 nm (106 inch lbs) then cap it off with the cap of the bleed screw. Lubricate the new Piston seal and brake caliper bore seal groove with brake fluid so that it is not twisted before fitting it. Apply the lubricant to the brake caliper bore and the Piston followed by installing the boot over the Piston, after which it should face the brake caliper housing Piston bore mouth, and it should be fixed in place. Then slide the Piston down to the bottom of the bore and make sure the whole boot is seated properly in both the grooves. Do the same for the other Piston, and put the brake caliper back onto the vehicle.