Vacuum Advance/Retard Component Test

1. Remove the vacuum lines from the vacuum advance/retard unit. Connect a vacuum pump to the hose connector on the advance side and create a vacuum of approximately 10 in./Hg. The breaker plate should move smoothly as vacuum is applied.
2. Hold this vacuum for approximately 15 seconds, then remove the vacuum hose. The breaker plate should smoothly 'snap' back to its' rest position.
3. Connect the vacuum pump to the hose connector on the retard side of the advance/retard unit.
4. Create a vacuum of approximately 10 in./Hg and hold it for approximately 15 seconds. The breaker plate should move smoothly as vacuum is applied.
5. If the vacuum did not hold for 15 seconds, replace the vacuum advance/retard unit.