Vacuum Pumps
Vacuum pumps are a safety critical component, providing vacuum for:

• Brake Servo’s

• EGR Valves

• Central Locking and other safety/comfort systems

Technology Types

The different types of vacuum pump work through ‘positive-displacement’ to move air from the vacuum system, and then through the crankcase ventilation and into the air intake system.

Rotary Vane Pumps – consist of vanes mounted to an offset rotor that rotates inside a cavity. Vacuum pressure is provided as air is moved from a larger chamber through to a smaller chamber. Click on the link to the right to see a demo of the rotary vane pump movement.

Diaphragm Pumps – consist of a chamber sealed with a flexible diaphragm. As the diaphragm flexes, the volume in the chamber is increased/decreased to provide vacuum pressure.

Piston Pumps – consist of a piston and chamber assembly where the piston moves up and down to increase/decrease the volume of the chamber to provide vacuum pressure.

Troubleshooting and Diagnostics

Common reasons for vacuum pump failures include:

• Lack of lubrication (usually taken from the engines oil circuit)

• Dirtying/aging of the lubrication oil/fluid

• Mounting faults and incorrect installation

• Normal wear and tear

When a pump starts to fail, vacuum controlled systems as outlined above will also start to fail and the OBD system may register a fault by illuminating the warning lamp.