Attention:
- The vacuum created is affected by engine temperature, operation of attachments and altitude;
- The vacuum created decreases by approximately 3 kPa for every 305 m above sea level.
1. Disconnect the vacuum hose from the vacuum booster check valve.
2. Connect a vacuum gauge to the hose.
3. Start the engine at idle speed and warm it up to operating temperature.
4. If on, turn off the air conditioner. With the engine idling, read the vacuum gauge. Nominal vacuum is 47-68 kPa.
5. Turn off the ignition.
6. If the vacuum created is normal, proceed to step 10.
7. If the vacuum is low, assess the condition of the vacuum hose and check that it is securely connected to the engine.
8. Eliminate the defects found and repeat the operations in points 2-4.
9. If no hose defects are found, check the engine condition.
10. Remove the vacuum booster check valve.
11. Connect the valve to the engine vacuum hose.
12. Connect a vacuum gauge to the valve.
13. Start the engine at idle speed.
14. After the vacuum gauge readings have stabilized, turn off the ignition.
15. Check how the check valve maintains the vacuum.
16. If the vacuum is maintained, proceed to step 18.
17. If the vacuum is not maintained, replace the check valve and repeat the operations in paragraphs 11-15.
18. Check the check valve sealing ring, look for signs of:
- weakening of the vacuum booster seat;
- deformations or contamination;
- keratinization, cuts and other defects.
19. If any defects are found, replace the sealing ring.