Disassembly Procedure
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, 2004 Chevrolet Cab & Chassis Silverado, and 2003 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
- Remove the brake master cylinder from the vehicle. Refer to Master Cylinder Replacement (Vacuum Boost) or Master Cylinder Replacement (Hydraulic Boost) .
- Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.
- Clean the outside of the master cylinder reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
- Remove the reservoir cap and diaphragm from the reservoir.
- Inspect the reservoir cap and diaphragm for the following conditions. If any of these conditions are present, replace the affected component(s).
- Cuts or cracks
- Nicks or deformation
- Remove the master cylinder reservoir from the master cylinder. Refer to Master Cylinder Reservoir Replacement .
- Using a smooth, round-ended tool, depress the primary piston (2) and remove the piston retainer.
- Remove the primary piston assembly from the cylinder bore.
- Plug the cylinder inlet ports and the rear outlet port. Apply low pressure, non-lubricated, filtered air into the front outlet port, in order the remove the secondary piston (1) with the primary (6) and secondary (5) seals, and the return spring.
- Discard the primary piston assembly, the piston retainer, and the seals and seal retainer from the secondary piston.