GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 370589  Size: SH
  1. Remove the master cylinder from the vehicle. Refer to Master Cylinder Replacement in Hydraulic Brakes.
  2. Drain the brake fluid from the reservoir.
  3. Secure the master cylinder in a vise. Do not clamp the master cylinder body, secure only the flange.

  4. Object Number: 370588  Size: SH
  5. Remove the reservoir body by pulling the body straight up and away from the cylinder body.
  6. Remove the seals from the reservoir.

Installation Procedure

  1. Inspect the reservoir for cracks or deformation. If found, replace the reservoir.
  2. Clean the reservoir with denatured alcohol, or equivalent.
  3. Dry the reservoir with non-lubricated, filtered air.
  4. Lubricate the new seals and the outer surface area of the reservoir-to-housing barrels with Delco Supreme 11® GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.

  5. Object Number: 370588  Size: SH
  6. Insert the O-rings into the grooves in the reservoir. Make sure that the O-rings are properly seated.
  7. Install the reservoir to the master cylinder body. Use your hand in order to press the reservoir straight down into the body.
  8. Install the master cylinder. Refer to Master Cylinder Replacement in Hydraulic Brakes.