System Component Description

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: System Component Description Flow Chart

Courtesy of GENERAL MOTORS CORP.

The hydraulic brake system consists of the following:

Hydraulic Brake Master Cylinder Fluid Reservoir: Contains supply of brake fluid for the hydraulic brake system. Provides for brake fluid to be drawn back into and vented back from the master cylinder primary piston and secondary pistons. Also provides for brake fluid to be drawn into the motor driven pump and high pressure accumulator (HPA) areas of the brake modulator assembly, and vented back from various areas of the modulator assembly as needed. Provides markings for both the MIN and MAX parameters of the pressurized or operating range; and for the maximum depressurized or system OFF level.
Hydraulic Brake Master Cylinder: Converts mechanical input force into hydraulic output pressure. During normal operation, hydraulic output pressure is distributed from the primary piston of the master cylinder through hydraulic circuits to the pedal feel simulator within the brake modulator assembly. Hydraulic pressure for the wheel apply circuits is generated by a motor driven pump and stored by a high pressure accumulator (HPA) within the modulator assembly. This pressurized fluid is distributed through valves to the rear apply circuits and to the secondary pistons of the master cylinder which, in turn, distribute pressurized fluid to the front wheel apply circuits.
Hydraulic Brake Pipes and Flexible Brake Hoses: Carries brake fluid to and from hydraulic brake system components.
Hydraulic Brake Wheel Apply Components: Converts hydraulic input pressure into mechanical output force.

The brake assist system consists of the following:

Brake Pedal: Receives, multiplies and transfers brake system input force from the driver.
Brake Pedal Pushrod: Transfers multiplied input force received from the brake pedal to the brake booster.
Hydraulic Brake Modulator Assembly: Contains several high pressure sensors, valves, solenoids and filters as well as a motor driven pump, high pressure accumulator (HPA), high pressure filter, pedal feedback or pedal simulator and the electronic brake control module (EBCM). The assembly monitors various sensor, control module and driver inputs to determine and command the optimal amount of brake fluid pressure needed for a given situation. The modulator assembly then blends and delivers the pressurized fluid to the wheel apply circuits as appropriate for correct braking balance and performance.