Vauxhall Workshop Service and Repair Manuals

Brake Servo, Check Function  

  Inspect   

With engine switched off, decrease vacuum in brake servo by actuating brake pedal several times. Depress brake pedal, keep under pressure and start engine. The brake system is in order, if the brake pedal continues to sink. If the brake pedal does not continue to sink, the vacuum system (vacuum line, non-return valve) must be checked. If no defect is determined there, the fault must lie with the brake servo itself.  
 
 
 
 
 

  Important!   

If the brakes on vehicles with diesel engines are pressed repeatedly in short and successive intervals over a long period of time, then the vacuum will be used up. The vacuum in the brake system is built up again if the brake pedal remains depressed with the engine running. As a result, the brake pedal moves downwards with the same brake pedal force. This is no reason to complain for vehicles with diesel engines as the pressure in the brake system is increased as a result of the brake assist force which is employed again. This may be demonstrated by connecting a pressure tester to a brake calliper.