OEM 2000 GMC Jimmy Brake Master Cylinder

2000 GMC Jimmy Brake Master Cylinder Parts and Q&A

• Q: How to overhaul the brake master cylinder on 2000 GMC Jimmy?

  A: Remove reservoir cap and drain off the brake fluid from the reservoir to overhaul the Brake Master Cylinder. Remove the reservoir and two grommets from the master cylinder body and clamp the master cylinder mounting flange in a vise. Disassemble by removing the snap ring and the primary Piston assembly, and then remove the seal. In order to pull out the secondary Piston with air pressure, place the open end of the cylinder bore approximately at a height of about 25 mm (1 inch) above a padded surface to collect the Piston with the use of very low air pressure so as to avoid suffering. After removing the secondary Piston, plug the rear port and pump air to the front port to peel down the seal then remove the spring retainer and spring. The components should be cleaned with denatured alcohol for metal components, and clean brake fluid for rubber components- ensuring that no impurities are remaining. Check the diaphragm for any damage and the cylinder bore for scratches or corrosion and replace the master cylinder if corrosion is present. Apply clean dot 3 motor vehicle brake fluid on the grommets, seals and on the cylinder bore, using new seals in assembly. Next, installation of the secondary Piston spring and spring retainer, primary seal and secondary seal for the secondary Piston. Push in the secondary Piston into the master cylinder body and install the seal on the primary Piston and the primary Piston assembly. Lock the assembly with the snap ring, pressuring the primary Piston when needed. Finally, add two new grommets to master cylinder, install the reservoir, and put the reservoir cap.