F 250 4WD LD Pickup V8-5.4L SOHC VIN L (1997)
Vacuum Brake Booster: Initial Inspection and Diagnostic Overview
Operational Check
1. Check the hydraulic brake system for leaks or insufficient fluid.
2. With the transmission in "neutral," stop the engine and apply the parking brake control. Apply the brake pedal several times to exhaust all vacuum in
the system.
3. Apply the brake pedal and hold it in the applied position. Start the engine. If the vacuum system is operating, the brake pedal will tend to move
downward under constant foot pressure. If no motion is felt, the power brake booster system is not functioning.
Visual Inspection
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.
