Vacuum unit

VACUUM UNIT

Vacuum gauge with connections for checking operation of vane-type vacuum unit

Checking operating faults

If the braking system is faulty, before replacing the vacuum unit, the vacuum circuit should be checked completely in accordance with the following procedure:

• with the engine off, empty the brake vacuum circuit fully by pressing the brake pedal to the floor several times;
• fit the vacuum gauge 1895899000 (3) between the one-way valve located on the vacuum unit (1) and the servo unit connecting pipe (2) (as shown in the drawing opposite);
• start the engine; after running the engine at idling speed for 20 seconds, the vacuum reading on the vacuum gauge (3) should be over 0.6 bar.

If the vacuum is under 0.6 bar, the servo unit connecting pipe (2) should be disconnected and the free end should be plugged with the special plug (4).

Re-start the engine; after running the engine at idling speed for 20 seconds, the vacuum reading on the vacuum gauge should be over 0.6 bar.

If it is, the fault should be sought in the air circuit or the servo unit.

If not, the vacuum unit is faulty and should be replaced.