Brake Booster, Basic Function - GF42.31-P-2004A

Model all (4xWD, CAR)

Fig 1: Brake Booster Components Location - Model All (4XWD, Car)

Courtesy of MERCEDES-BENZ USA

Example illustration

Overview

This document contains information on:

General
Function

General

The brake booster supports the pedal force applied by the driver when braking.

Function

The brake booster contains the following components:

Brake vacuum sensor
Position sensor
Solenoid
Indicator switch

The brake booster is supplied with vacuum by a vacuum line either from the electric vacuum pump, the combustion engine or the mechanical vacuum pump. If the brake is not operated, equal vacuum exists on both sides of the diaphragm. A compression spring holds the diaphragm plate in its starting position.

The travel sensor is designed as a potentiometer. It records both the pedal movement as well as the diaphragm movement of the brake booster.

If a high actuation speed (emergency braking) is detected, the solenoid is actuated. The work chamber of the brake booster is ventilated; the full boosting can take effect. Maximum full-stop braking takes place even if the pedal pressure implemented by the driver is insufficient. ABS regulation prevents the wheels from locking up. If the brake pedal is fully released, the indicator switch switches off the solenoids. Brake force boosting is completed.

Additional basic functions
Electromechanical brake booster, basic function	Model all (CAR) with code 200 (Conditionally automated driving)	GF42.31-P-2003A
	Model all (CAR) with code 503 (Remote-controlled parking)
	Model all with engine 177 with code ME10 (Hybrid vehicle (plug-in, PHEV))

Brake vacuum sensor, basic function		GF42.31-P-2002A