OEM Chevrolet Trailblazer Brake Master Cylinder

Chevrolet Trailblazer Brake Master Cylinder Parts and Q&A

• Master Cylinder
  15142479
  Q: How to overhaul the brake master cylinder on Chevrolet Trailblazer?

  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.
• Master Cylinder
  19209266
  Q: How to perform bench bleeding of the brake master cylinder on Chevrolet Trailblazer?

  A:

  You must secure the master cylinder mounting flange in a bench vise to properly conduct bench bleeding while having access to the rear side of the primary Piston. Set up suitable port fittings to match the required flare seat on the master cylinder ports and allow hose attachment before you remove the cap and diaphragm from the reservoir. Set up transparent hoses to the fittings and place them inside the master cylinder reservoir. Put delco supreme 11 brake fluid (GM part 12377967 or 992667 Canadian) or its equivalent dot-3 into the reservoir up to its halfway mark using a clean sealed brake fluid container while making sure both hose ends touch the fluid. Press and let go the primary Piston using a round-ended smooth tool for about 25 mm (1 inch) multiple times while observing the fluid exit from the ports. As primary and secondary pistons accept less air during the procedure their travel distance decreases and operation becomes more challenging. Press the primary Piston multiple times so fluid flows easily out of the ports without air bubbles. Follow these steps afterward: (1) take out the transparent hoses from the reservoir, (2) set back the master cylinder reservoir cap and diaphragm, and then (3) detach the fittings with the hoses from the ports while securing the master cylinder with cloth cover to catch spills before extracting it from the vise.