Hydro-Boost Power Brake

Hydro-Boost power brakes work using hydraulic fluid pressure (fed from the power steering pump) to "boost" the force on the master cylinder brake fluid, thereby applying more force to the brake caliper (and then on the rotor with brake pads). Both Hydro-boost power and vacuum assist are power braking systems, which can multiply the force you apply to the brake with the brake pedal, but hydro-boost power can produce a greater force than the vacuum assist system, and there is no need to use the vacuum of the engine.