A brake booster amplifies the force applied to the brake pedal, using engine vacuum or a hydraulic assist system to multiply pedal pressure before it reaches the master cylinder. A failing booster commonly causes a hard, high-effort brake pedal, a hissing sound near the firewall when braking, or in vacuum-assist systems, reduced power and a rough idle from a vacuum leak. Browse replacement brake boosters for cars, trucks, and SUVs to restore proper pedal assist and stopping power.
