GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Astro - 4WD 🢒 Preface 🢒 Cautions and Notices 🢒 Master Cylinder Reservoir Replacement

Disassembly Procedure

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

    3. Object Number: 370587 Size: SH
  3. Carefully tap out the reservoir retaining pins.

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

Assembly Procedure

    Object Number: 370588 Size: SH
  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) or equivalent DOT--3 brake fluid from a clean, sealed brake fluid container.
  5. Install the lubricated seals, make sure they are fully seated.
  6. Install the reservoir to the master cylinder by pressing the reservoir straight down on the master cylinder until the pin holes are aligned.

    7. Object Number: 370587 Size: SH
  7. Carefully tap the reservoir retaining pins into place to secure the reservoir.

    8. Object Number: 370589 Size: SH
  8. Install the diaphragm in the cover.
  9. Install the cover on the reservoir.
  10. Remove the master cylinder from the vice.
  11. Install the master cylinder. Refer to Master Cylinder Replacement .