Vacuum Brake Booster Check Valve: Testing and Inspection

Checking
1. Operate the brake pedal several times until the vacuum in the brake booster is reduced.
2. Connect vacuum tester (030) to brake booster as follows:
- Disconnect vacuum line (8) at booster (1).
- Install measurement connector tool (070). Tools and Equipment
Use shop made tool for screwed connection.
Use special tool No. 168 589 08 63 00 for plug type connection.
- Connect vacuum tester (030) to measurement connector (070).
3. Start engine and create a vacuum of 0.75-0.80 bar by opening the throttle and suddenly releasing the accelerator pedal.
- Reduce vacuum to less than 0.8 bar by operating the brake pedal.
4. Switch off engine.
- Vacuum must not drop by more than 0.2 bar in 30 seconds.
- If vacuum loss is greater than 0.2 bar, replace vacuum line (1).
- Check brake booster if necessary. Testing and Inspection
5. Install in reverse order, tighten screwed type vacuum line connection to brake booster to 30 Nm.