B350 1 Ton Van V8-5.9L VIN Z (1992)
Vacuum Pump: Testing and Inspection
1. Disconnect vacuum hose from servo, then install a vacuum gauge into hose.
2. Start engine and run at idle. Vacuum gauge should read 10 inches Hg.
3. Turn ignition switch to the Off position. Vacuum should hold at 10 inches Hg.
4. If vacuum gauge reads below 10 inches Hg, or does not hold, check for vacuum leaks, or poor engine performance.
