GM Service Manual Online
For 1990-2009 cars only

System Component Description

The brake assist system consists of the following:

Brake Pedal: Receives, multiplies and transfers brake system input force from driver.

Brake Pedal Pushrod: Transfers multiplied input force received from brake pedal to brake booster.

Hydraulic Brake Booster: Uses power steering fluid pressure to decrease effort required by driver when applying brake system input force. When brake system input force is applied, pressurized power steering fluid is admitted to the rear of an apply piston, providing a decrease in brake pedal effort required. When input force is removed, pressurized power steering fluid is blocked off from the piston.

Power Steering System: Supplies pressurized power steering fluid used by hydraulic brake booster to decrease brake pedal effort.

System Operation

Brake system input force is multiplied by the brake pedal and transferred by the pedal pushrod to the hydraulic brake master cylinder. Effort required to apply the brake system is reduced by the hydraulic brake booster.