COUPLING GP-PUMP 4310547 - Caterpillar

Illustration 1 g01261878
Location of the service brake pedal
Illustration 2 g01261880
(1) Brake pedal position sensor
(2) Tank port
(3) Supply port
(4) Brake portThe foot brake valve for the service brakes is located in the cab.The brake position sensor provides an input to the brake ECM, and sends the signal to the brake ECM about the position of the brake pedal. If the truck is equipped with wet brakes, the brake position sensor will cause the brake ECM to command current to the front brake solenoid. If the truck is equipped with the standard dry front brakes, and the front brakes are locked out via the front brake lockout switch, the application of the brake pedal results in no braking by the front wheels. If the dry front brakes are not locked out via the front brake lockout switch, the application of the brake pedal will command the front brakes. The brake pedal position sensor is a PWM sensor. The sensor needs no manual calibration or adjustment. The brake position sensor automatically calibrates when the truck is started.Oil from the brake charge pump flows through the cab brake valve to supply port (3) of the foot brake valve.When the service brake control is depressed, internal passages in the foot brake valve route the supply oil to brake port (4). This oil flows back through the cab brake valve to the rear slack adjuster. The oil flows from the slack adjuster to actuate the rear service brakes.When the service brake control is released, the oil that is returning through the brake port is routed to the hydraulic tank through tank port (2).