Power Brake Booster
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix and 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
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.