Ford F150 Pickup. Instruction - part 411

repair or replacement:  

z

Low brake fluid level detected without signs of leakage. This condition is caused by displacement of 
brake fluid to the disc brake calipers to compensate for normal brake wear. Add brake fluid as needed.  

z

A momentary or slight squirt of brake fluid from the brake master cylinder reservoir (2K478) upon 
application of the brake pedal.  

z

A trace of brake fluid found on the outside of the power brake booster below the brake master cylinder 
mounting flange. This condition results from the lubricating action of the brake master cylinder wiping 
seal.  

Warning Switch, Brake Fluid Level 

 

2003 Ford Pickup F150 

2003 BRAKES Hydraulic Brake Actuation - F150 Pickup

  

Fig. 4: Warning Switch, Brake Fluid Level 
Courtesy of FORD MOTOR CO. 

The brake master cylinder fluid level warning switch is an integral part of the brake master cylinder reservoir. It 
consists of a float containing a magnet and a reed switch mounted in the bottom of the brake master cylinder 
reservoir. 

When the brake fluid in the brake master cylinder reservoir gets to a predetermined level, the floating magnet 
actuates the reed switch, causing the red brake warning indicator to illuminate. Loss of brake fluid from either 
the primary (front) hydraulic circuit or secondary (rear) hydraulic circuit will cause the warning indicator to 
activate. If the brake fluid level warning switch is inoperative, the brake master cylinder reservoir must be 

 

2003 Ford Pickup F150 

2003 BRAKES Hydraulic Brake Actuation - F150 Pickup

  

installed new. 

Brake Tubes & Hoses 

When installing new hydraulic brake tubing, hoses, or connectors, tighten all connections securely. After 
installation, bleed the brake system. For additional information, refer to BLEEDING BRAKE SYSTEM . 

DIAGNOSIS & TESTING 

HYDRAULIC BRAKE ACTUATION 

Refer to DISC - BLACKWOOD, F150 HERITAGE PICKUP & F150 PICKUP . 

REMOVAL AND INSTALLATION 

PEDAL & BRACKET - FIXED, AUTOMATIC TRANSMISSION 

Removal 

1. Disconnect the battery ground cable. For additional information, refer to BATTERY, MOUNTING 

AND CABLES .  

2. Remove the stoplight switch self-locking pin. 

 

2003 Ford Pickup F150 

2003 BRAKES Hydraulic Brake Actuation - F150 Pickup

  

Fig. 5: Removing Stoplight Switch Self-Locking Pin 
Courtesy of FORD MOTOR CO. 

3. Slide the stoplight switch and booster push rod off the brake pedal pin. 

 

2003 Ford Pickup F150 

2003 BRAKES Hydraulic Brake Actuation - F150 Pickup