For 1990-2009 cars

### 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.
Vacuum Brake Booster: Uses source vacuum to decrease effort required by driver when applying brake system input force. When brake system input force is applied, air at atmospheric pressure is admitted to the rear of both vacuum diaphragms, providing a decrease in brake pedal effort required. When input force is removed, vacuum replaces atmospheric pressure within the booster.
Vacuum Source: Supplies force used by vacuum brake booster to decrease brake pedal effort.
Vacuum Source Delivery System: Enables delivery and retention of source vacuum for vacuum brake booster.

### 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 vacuum brake booster.