Brake Booster

A booster is a mechanical or vacuum device that is attached to the master cylinder in power brake systems. The function of the brake booster is to increase the power and effectiveness of brake systems. Vacuum boosters tap into the vacuum created by the engine, and use this to assist braking. In some systems, the booster is connected to the power steering system. In this case, the power steering pump supplies pressurized fluid to the booster cylinder. All boosters are designed to assist braking force from the pedal, not to provide all of the braking force. This is done as a safety feature in case the engine quits, cutting off the booster's power supply. Some boosters use electrical motors to generate their power, which allows them to remain effective without the engine running.