Vacuum System, Checking For Proper Seal

Vacuum System, Checking For Proper Seal

Check hose setup
- Disconnect vacuum line at intake manifold.







- Connect V.A.G 1390 hand vacuum pump to disconnected vacuum line.
- Operate hand vacuum pump at least 50 times (Vacuum build-up must be noticeable when operating).
- Disconnect hose from hand vacuum pump.

During this, vacuum must be released only between hand vacuum pump and check-valve
- If further vacuum is audibly released, check-valve is leaky (replace check-valve).

Checking vacuum diaphragm
- Disconnect vacuum line from vacuum diaphragm for intake manifold change-over.
- Connect hand vacuum pump directly to vacuum diaphragm.
- Operate hand vacuum pump and observe change-over procedure during this.
- Check vacuum reservoir for proper seal.
Specified value: Vacuum diaphragm must not return to output position, as long as the hand vacuum pump is not vented.

If the vacuum diaphragm moves back.
- Replace vacuum diaphragm.