GM Service Manual Online
For 1990-2009 cars only

Master Cylinder

Master Cylinder


Object Number: 176843  Size: SF
(1)Proportioning Valve Caps
(2)Proportioning Valve Caps O-Rings
(3)Proportioning Valve Springs
(4)Proportioning Valve Pistons
(5)Proportioning Valve Seals
(6)Master Cylinder Reservoir Cap
(7)Master Cylinder Reservoir Diaphragm
(8)Master Cylinder Fluid Level Sensor
(9)Master Cylinder Reservoir
(10)Master Cylinder reservoir O-Rings
(11)Master Cylinder
(12)Spring
(13)Spring Retainer
(14)Seal
(15)Secondary Piston
(16)Seal
(17)Primary Piston
(18)Retainer
(19)Master Cylinder Reservoir Spring Pins

Important: 

   • Replace all of the components that are included in the repair kits used to service this master cylinder.
   • Lubricate the rubber parts with clean brake fluid in order to ease assembly.
   • Do not use lubricated compressed air on the brake parts. This action may cause damage to the rubber components.
   • If you remove or disconnect any hydraulic part, you may have to bleed all or part of the brake system.
   • The specified torque values are for dry, non-lubricated fasteners.
   • Perform the service operations on a clean bench that is free from all mineral oil materials.

This master cylinder is a composite design with a plastic reservoir and an aluminum body. The master cylinder is used in a diagonally split system. In this system, one front and one diagonally rear brake is served by the primary piston, and the opposite front and rear brakes are served by the secondary piston.

The master cylinder incorporates the functions of a standard dual master cylinder. The master cylinder also has a fluid level sensor. The integral proportioning valves are designed to provide better front-to-rear braking balance with a heavy brake application.

Fluid Level Sensor

The compact master cylinder is equipped with a fluid level sensor. The sensor switch is located in the inboard side of the reservoir. The sensor activates the BRAKE warning lamp if the fluid level is low. The BRAKE warning lamp turns off when the fluid level is corrected. For electrical details on the BRAKE warning system, refer to Brake Warning System Schematics .