Vacuum Advance
Remove distributor cap. Remove both vacuum hoses from advance diaphragm. Connect Vacuum Pump/Gauge (A973X-041-XXXXX ) to advance diaphragm "A" (inside port). Apply 20 in. Hg vacuum. Stator should turn clockwise and stay. When vacuum is released, stator should return to normal position. Repair or replace stator as necessary. Repeat procedure for vacuum diaphragm "B" (outside port).