Section 06-00: Brake System, Service
1996 F-150, F-250, F-350, F-Super Duty Chassis Cab, Motorhome Chassis and Bronco Workshop Manual
SERVICE PROCEDURES

Brake System Test Procedure

Air Trapped In Brake System

To test for the presence of air in the brake system, refer to Pinpoint Test F in this section.

Brake Pedal Reserve Check

Where a low brake pedal (2455) or the feel of a bottomed-out condition exists, check for brake pedal reserve.

  1. Operate engine (6007) at idle with the transmission (7003) in either PARK or NEUTRAL.

  1. Depress brake pedal lightly three to four times.

  1. Allow 15 seconds for vacuum to replenish power brake booster (2005).

  1. NOTE: Increased resistance may feel like the brake pedal has bottomed out.

    Apply brake pedal until it stops moving downward or an increased resistance to the brake pedal travel occurs.

  1. Hold brake pedal in applied position and raise the engine speed to approximately 2000 rpm.

  1. NOTE: The additional movement of the brake pedal is the result of the increased engine manifold vacuum which exerts more force on the power brake booster during engine rundown. This means that additional stroke is available in the brake master cylinder (2140) and the brake system is not bottoming out as a customer may believe.

    Release accelerator pedal and shaft (9725) and observe that brake pedal moves downward as engine returns to idle speed.