OEM 2006 GMC Envoy Brake Master Cylinder

2006 GMC Envoy Brake Master Cylinder Parts Questions & Experts Answers

• Q: How to overhaul the brake master cylinder on 2006 GMC Envoy?

  A: To overhaul the brake master, first of all, pull out of the vehicle and clamp the mounting flange in a bench vise, making sure the rear of the primary Piston is accessible. Stress cleaning the area surrounding the reservoir cap and then unfastening it along with the diaphragm, and checking both for cuts, cracks, nicks, and deformation, and replacing any damaged parts. Remove the master cylinder reservoir, and with a smooth, round-ended tool press the primary Piston to release the Piston retainer and follow with the primary Piston assembly from the cylinder bore. Connect the cylinder inlet ports and the back outlet port, then put on the low pressure, non-lubricated, filtered air into the front outlet port to drop the secondary Piston, primary, and secondary seals and return spring, discarded the primary Piston group, Piston retainer and seals. Clean master cylinder, secondary Piston, and return spring, checking for cracks, scoring, pitting or corrosion and replace master cylinder if any problems are present. Dry all components with non-lubricated, filtered air and lubricate the master cylinder bore, secondary Piston , return spring, and all overhaul components with delco supreme ii® (GM P/N 12377967, Canadian P/N 992667) or equal brake fluid from a clean, sealed container of the dot-3 type. Put together the new primary seal and retainer, and new secondary seal onto the secondary Piston and put the lubricated return spring and secondary Piston assembly into the cylinder bore; then put in the new primary Piston assembly that is lubricated. Press in the primary Piston with a smooth round-ended tool to get in the new Piston retainer then in reattach the master cylinder reservoir and its cap and diaphragm before getting the final installation on the master cylinder into your vehicle.