GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Envoy - 4WD 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Master Cylinder Reservoir Replacement

Removal Procedure
  1. Remove the master cylinder. 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: 176838 Size: SH
  3. Carefully remove the reservoir retaining pins.
  4. Remove the reservoir body by pulling the body straight up and away from the cylinder body.

    5. Object Number: 230993 Size: SH
  5. Remove the seals from the master cylinder.
  6. Inspect the reservoir for cracks or deformation. Replace the reservoir if necessary.
  7. Clean the reservoir with clean denatured alcohol.
  8. Dry the reservoir with non-lubricated compressed air.

Installation Procedure

    Object Number: 230993 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. Insert the lubricated seals, make sure they 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: 176838 Size: SH
  7. Carefully install the reservoir retaining pins to secure the reservoir.
  8. Remove the master cylinder from the vise.
  9. Install the master cylinder. Refer to Master Cylinder Replacement .