How do power brake boosters and master cyinders work in a auto's brake system?

Question

How do power brake boosters and master cyinders work in a auto's brake system?

Answer 1

heres a good site to start learning about it.

Answer 2

A brake booster adds force to the foot operated brake pedal to reduce effort placed on the brake pedal and increase operator ease of use.



A brake booster has a servo valve in it which senses the position of the pedal when you push it. As soon as you push the pedal, the servo valve senses the "request" for more force, and closes a valve. This valve connects a pressure chamber to the engine vaccum. The pressure difference acts on a large diaphragm in the round booster can, adding force to the brake master cylinder, pressing harder on the brake pads. If the driver stops pressing down, the servo valve opens and maintains a constant pressure difference across the helper diaphragm. When the pedal is released, the servo valve dumps the vacuum and the pressures are equalized across the diaphragm. On diesel light trucks and older Volkswagen diesel cars, a vacuum pump is run off the engine to power the brake booster.



With the introduction of electric hybrids, they are returning back to the hydraulically boosted brakes that run off the power steering pump. They use the fluid and a servo valve to accomplish the same task as vacuum on a diaphragm. Cadillac invented this system years ago and it was used in some IH trucks.