Vacuum servo

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Brake booster from a Geo Storm. 2008-05-05 1990 Geo Storm GSi vacuum servo.jpg
Brake booster from a Geo Storm.
Brake vacuum servo section Servofreno seccionado.jpg
Brake vacuum servo section

A vacuum servo (also called a brake booster, power booster, or power brake unit) is a component used on motor vehicles in their braking system, to provide assistance to the driver by decreasing the braking effort. It uses a vacuum, usually supplied by the engine, to multiply the driver's pedal effort and apply that effort to the master cylinder. [1]

Contents

Because the servo depends on the vacuum supplied by a running engine, a check valve is typically used in the vacuum line to maintain residual vacuum without engine support, allowing limited use even after parking.

The system was invented by Albert Dewandre [2] who, together variously with Bosch and Clayton-Dewandre Ltd. took out further patents as it was refined. [3]

See also

Notes

  1. "Learn about Hydraulic Brakes - How a vacuum brake servo/booster works". edumech.co.uk. Archived from the original on 2016-04-25. Retrieved 2025-06-25.
  2. "History Bosch servo brakes". Bosch Global. Retrieved 23 October 2025.
  3. "Improvements in or relating to hydraulic braking systems". 30 March 1936. Retrieved 23 October 2025 via google.