OEM 2003 Cadillac CTS Brake Master Cylinder

2003 Cadillac CTS Brake Master Cylinder Parts and Q&A

• Q: How to overhaul the brake master cylinder on 2003 Cadillac CTS?

  A: Start by removing the master cylinder from the vehicle and place the mounting flange into a bench vise so you can easily access the rear of the primary Piston. First wash the master cylinder reservoir cap area and afterwards thoroughly examine the cap and diaphragm for damages before replacing any compromised components. You should extract the master cylinder reservoir then use a smooth tool with a round end to depress the primary Piston while removing the Piston retainer before pulling out the primary Piston assembly from the cylinder bore. Plugging the cylinder inlet ports and rear outlet port you can push low pressure filtered air through the front outlet port to remove the secondary Piston assembly and its primary and secondary seals and the return spring. The technician should dispose of the initial Piston assembly, Piston retainer, and seals that are present on the secondary Piston. Denatured alcohol cleans the interior and exterior surfaces of the master cylinder and secondary Piston and return spring while an inspection checks for cracks, scoring, pitting, and corrosion before replacing the master cylinder when issues appear. Apply delco supreme 11 brake fluid gm p/n 12377967 (Canadian P/N 992667) or equivalent dot-3 brake fluid from a clean, sealed container to lubricate the master cylinder bore, secondary Piston and return spring and all overhaul components. Dry components with non-lubricated filtered air before the lubrication process. Lubricate the new primary seal and retainer assembly with fresh secondary seal before attaching it to the secondary Piston. After that, place the lubricated return spring with secondary Piston assembly into the cylinder bore and finally install the lubricated new primary Piston assembly. Use a smooth tool to depress the primary Piston then install the new Piston retainer. First attach the master cylinder reservoir followed by installing the reservoir cap alongside the diaphragm before reinstalling the master cylinder to its original position in the vehicle.