PULLEY-FAN 3848712 - Caterpillar

Stop the engine. Engage the parking brake. Depress the brake pedal repeatedly until there is no brake oil pressure. Pause for 2 seconds between each of the applications.
Connect the Communication Adapter Tool to a laptop computer that is equipped with Caterpillar Electronic Technician (ET). Connect the Communication Adapter Tool to the data link connector. Note: The brake system pressure must be monitored with ET.
Observe the pressure. Before you start the engine, the oil pressure should be 0 kPa (0 psi).
Start the engine. The oil pressure will increase to a maximum. Record this pressure. This value is the cutout pressure of the charging system for the brake accumulators.
Apply the service brakes repeatedly while the engine is running. Verify that the pressure drops consistently. Record the point, when the pressure begins to increase quickly. This value is the cut-in pressure.
Stop the engine. Immediately turn the engine start key to the ON position but do not start the engine. The warning indicator for the brake system should illuminate for 3 seconds while the dash panel cluster performs a start-up test. If any of the warning lights do not illuminate, you may need to replace the dash panel cluster.
Depress the brake pedal until the pressure gauge decreases to approximately 10350 kPa (1500 psi). The warning light on the dash for the low brake oil pressure should illuminate. A minimum of three applications of the service brake pedal are required. If warning light does not illuminate, replace the pressure sensor.
Continue depressing the brake pedals after the warning light for low brake pressure illuminates. Watch for a rapid decrease in the brake pressure. Record the pressure, when the pressure decreases rapidly. This value is the approximate nitrogen precharge pressure in the brake accumulator. If the nitrogen precharge pressure is not within the specification, then go to the "Charging the Brake Accumulators".
Remove all of the test equipment. Charging the Brake Accumulators
Table 3
REQUIRED TOOLS
Part Number Description Quantity
175-5507 Nitrogen Charging Group 1 Stop the engine. Depress the brake pedal repeatedly until there is no brake pressure.To ensure that the nitrogen charge is correct, each brake accumulator piston must be at the bottom of the accumulator cylinder. Nitrogen gas pressure varies with the temperature. To obtain the most accurate nitrogen charge, the temperature of each accumulator must be identical to the air temperature around the accumulators.
Table 4
Charging Pressure and Temperature Relationship for a Typical 5515 kPa (800 psi) Accumulator
Temperature °C (°F) Pressure kPa (psi)
−7 °C (20 °F) 4990 kPa (724 psi)
−1 °C (30 °F) 5103 kPa (740 psi)
4 °C (40 °F) 5196 kPa (754 psi)
10 °C (50 °F) 5309 kPa (770 psi)
16 °C (60 °F) 5421 kPa (786 psi)
21 °C (70 °F) 5515 kPa (800 psi)
27 °C (80 °F) 5627 kPa (816 psi)
32 °C (90 °F) 5721 kPa (830 psi)
38 °C (100 °F) 5834 kPa (846 psi)
43 °C (110 °F) 5927 kPa (860 psi)
49 °C (120 °F) 6040 kPa (876 psi) If an accumulator has less