TANK GP-FUEL 2783898 - Caterpillar

Sudden movement of the machine or release of air under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the air system and brakes.
Start the tractor engine and allow the pressure to reach the cut-out pressure. The cut-out pressure is 827 34 kPa (120 5 psi).
Illustration 1 g00724838
View of the Right Side of the Operator Compartment (1) Parking brake control
Place parking brake control (1) in the DISENGAGED position. The control is in the DISENGAGED position when the knob is depressed. Stop the engine.
Push the brake pedal rapidly for several times, until the knob automatically moves to the ENGAGED position.
Read the pressure on the test gauge. See Testing and Adjusting, "Air Pressure Gauge - Test" for the installation of the gauge.
The correct pressure that will automatically engage the brakes is 379 34 kPa (55 5 psi). If the pressure on the gauge is not correct, the operation of the parking brake control is not correct.
Check for worn parts or damaged parts. Check for damaged wires or loose wires.
If this does not correct the problem, proceed to Testing and Adjusting, "Solenoid Valve (Parking Brake) - Test".
If this does not correct the problem, install a new parking brake control.