Vacuum Operated Servo

Manufacturer: Ate/Teves
Type: Vacuum Assisted
Diameter: 203 mm (8 inch)
Power Amplification: 4:1 (at 300 N (66 ft lb) pedal pressure)

The servo unit reinforces the driver's pedal effort when the brakes are applied. The reinforcement of the force applied which is achieved through the servo unit is obtained from the vacuum in the engine intake manifold, and amounts to around 4:1. The servo unit is connected to the intake manifold by a hose.
The servo can produce an increase in pressure of up to 80 bar.

Brakes Off





In the rest position (brakes off), the air passage (4) is closed and the vacuum chamber (8) is connected to the working chamber (6) via the open cross over valve (3). Equal vacuum exists on both sides of the diaphragm (1) in the brakes off position.

Brakes Applied





As the brake pedal (11) is depressed, the vacuum passage (2) is closed and the air passage (4) is constantly open. The greatest possible pressure difference acts on the diaphragm (1) and the maximum brake pressure is obtained.