Vacuum Brake Booster Check Valve: Testing and Inspection
Vacuum pump and control valve, check
Special tools:
999 5230 PRESSURE METER 999 5230 Pressure Meter
Preparations
Remove the control valve from the brake booster.
Connect gauge 999 5230 PRESSURE METER 999 5230 Pressure Meter to the valve in the socket of the brake booster.
Remove the vacuum line at the induction pipe. Plug the socket of the induction pipe.
Note! When the ignition is on (engine not started) and a vacuum is created, the electric auxiliary pump is activated. It runs only a few seconds due to the system relay.
Checking the vacuum control valve
Start the engine
See below, checking the control valve
Turn off the engine
Fit the vacuum line to the induction pipe.
Checking the vacuum pump
- Remove the quick coupling of the vacuum line at the vacuum pump.
- Fit gauge 999 5230 PRESSURE METER 999 5230 Pressure Meter on the pump.
- Start the engine and read the gauge.
The value should lie between 80-90 kPa negative pressure.
- Turn off the engine
- The vacuum should not sink too quickly (If the pump has difficulty reaching 80-90 kPa negative pressure, replace it).
- Remove the pressure gauge
- Fit the vacuum line's quick coupling on the pump.
Checking the non-return valves in the vacuum control valve.
Blow or suck in the connection to the brake booster.
If it can be blown, it is OK.
If it cannot be sucked, it is OK.
Fit the control valve on the brake booster.
Remove the vacuum line at the induction pipe (press in the plastic ring towards the induction pipe and pull out the line).
Blow or suck in the line.
If it cannot be blown, it is OK.
If it can be sucked, it is OK.
Fit the vacuum line on the induction pipe.
Remove the quick coupling at the vacuum pump.
Blow or suck in the line.
If it cannot be blown, it is OK.
If it can be sucked, it is OK.
Fit the vacuum line's quick coupling on the vacuum pump.
Check
Start the engine and check that the brake booster receives a negative pressure.
Brake repeatedly and listen to hear if the vacuum pump starts.