OEM GMC Sierra 1500 Classic Brake Master Cylinder

GMC Sierra 1500 Classic Brake Master Cylinder Parts and Q&A

• Master Cylinder
  19209236
  Q: How to service and repair the Brake Master Cylinder on GMC Sierra 1500 Classic?

  A:

  To fix the Brake Master Cylinder start by fastening its mounting flange in a bench vise to reach its rear. Secure fittings near the master cylinder ports for flare seating that can connect to hoses and remove the diaphragm and reservoir cap. Insert transparent hoses to these fittings then guide them into the master cylinder reservoir. Pour delco supreme ii brake fluid (GM P/N 12377967 or equivalent DOT-3 brake fluid) into the master cylinder reservoir until the liquid reaches half its volume through hose ends that must be completely dipped into the fluid. Press the primary Piston down 25mm using a rounded tool and let it return to its starting position until the fluid flows smoothly across ports. Pressing the primary Piston will become harder and its travel shorter as it pushes air out of the system. Maintain this procedure until brake fluid emerges fully from the openings without air content. Put the master cylinder reservoir back on then connect the end fittings to port openings before taking the master cylinder out from the vise.
• Master Cylinder
  19209239
  Q: How to replace the Brake Master Cylinder (Hydraulic Boost) on GMC Sierra 1500 Classic?

  A:

  First apply the parking brake and disable the wheels before working on the hydraulic boost master cylinder. To prevent brake fluid loss seal the exposed brake pipe openings with a rubber cap before detaching the Brake Fluid Level Sensor connector. Seal the brake pipe openings at both ends by plugging them after you disconnect the brake pipes from their connection with the master cylinder. Pull out the master cylinder by removing its mounting nuts before you take it from the vehicle and separate the master cylinder reservoir. Begin the installation process by adding the master cylinder reservoir first and then bench bleed the master cylinder. Reinstall the master cylinder into its vehicle position and fasten it firmly with mounting nuts at 33 nm (24 ft. Lbs). Connect the brake pipes by putting their open ends together and tighten the pipe fittings to 25 nm (18 ft. Lbs.). Connect the Brake Fluid Level Sensor electrical connector and drain the brake hydraulic system. To end the process release the parking brake and take away wheel obstructions.