F 350 2WD Pickup V8-460 7.5L VIN G EFI (1997)
Vacuum Brake Booster: Component Tests and General Diagnostics
Inspect all hoses and connections. All unused vacuum connectors should be capped. Hoses and their connections should be properly secured and in good
condition with no holes or collapsed areas.
1. Remove vacuum booster hose from power brake booster and check valve connection. Manifold vacuum should be available at the check valve end
of the vacuum booster hose with engine at idle speed and transmission in NEUTRAL. If manifold vacuum is available to the power brake booster,
connect vacuum booster hose to power brake booster and repeat Steps 2 and 3 above. If no downward movement of brake pedal is felt, replace
power brake booster.
2. Operate engine a minimum of 10 seconds at fast idle. Stop engine, and let vehicle stand for 10 minutes. Apply brake pedal with approximately 89
N (20 lb) of force. Brake pedal feel should be the same as that noted with engine operating. If brake pedal feels hard (no power assist), replace
check valve and retest. If brake pedal feels spongy, bleed hydraulic system to remove air.