3239169 - 3330DA Check operation of brake servo vacuum circuit and vacuum unit

Fully depress the brake pedal repeatedly to completely drain the vacuum circuit.Disconnect the pipe connected to the brake servo from the vacuum unit and connect the tool.

NameCountry
1Vacuum gauge1.895.899.001
Start up the engine and, after 20 seconds (with the engine idling), check, on the vacuum gauge, that the pressure is > 0.6 bar.If the value measured is less than 0.6 bar or close to 0.9 bar, disconnect the vacuum gauge pipe from the brake servo pipe.Fit the special plug for the tool on the vacuum gauge pipe.

NameCountry
2Vacuum gauge1.895.899.001

Start up the engine and, after 20 seconds, check, the the vacuum gauge, that the reading is above 0.6 bar:

  • if this is the case, the fault should be sought in the vacuum circuit or in the brake servo
  • if this is not the case, the vacuum unit is faulty.