PLATE 4831525 - Caterpillar

Personal injury can result if the machine moves while testing.If the machine begins to move during test, reduce the engine speed immediately and engage the parking brake.
Sudden movement of the machine or release of oil 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 brake system.
Table 1
Required Tools    
Tool     Part Number     Description     Qty    
A     198-4240     Digital Pressure Indicator Gp     1    
Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel. Place the transmission direction control lever in the NEUTRAL position. Engage the parking brake. Lower the bowl to the ground. Stop the engine and put chocks in front of the wheels and behind the wheels.
Start the engine and run the engine with the transmission in neutral and the parking brake engaged. Allow the hydraulic oil to reach normal operating temperature. Then shut off the engine.
Pump the brake down approximately 110 times by using full even strokes.Note: Do not assume that the pressure is removed from the circuit if the brake pedal has no resistance.
Illustration 1 g01615660
View of the rear of the box that contains the accumulators (1) Test port (2) Test port
Remove the dust cover from test port (1) and (2). Install tooling (A) onto the test ports (1) and (2) .
Run the engine at a low idle. Pump the brakes until the cut in pressure of 15850 515 kPa (2300 75 psi) is reached. The pump will begin to charge the accumulators.
Place the parking brake switch in the off position. Turn the ignition key to the off position and allow the engine to shut down. Then return the key to ON.
Lower the service brake pressure in the system by pumping the service brake pedal at a rate of one second ON and one second OFF. Count the number of applications of the brake pedal that are required in order to lower the system's pressure. The indicator lamp for the parking brake will then begin to flash.Note: The low pressure warning must have activated at a higher pressure than the parking brake indicator.
Start the engine on the machine. Operate the machine at low idle and set the parking brake. Then release the service brakes. the accumulator pressure should decrease from cut out pressure to cut-in pressure in less than 30 seconds.The maximum pressure on the gauges is the cut out pressure. The cut out pressure should be 19120 515 kPa (2775 75 psi).
Pump the service brake pedal. The minimum pressure on the gauge is the cut-in pressure. The cut in pressure should be 15850 515 kPa (2300 75 psi).
Continue to run the engine at a low idle while the accumulators charge. Verify that the pump standby pressure is 2755 690 kPa (400 100 psi).
Illustration 2 g01617153
Top view of the accumulator charging valve and