PAN GP-OIL 2964640 - Caterpillar

Specifications
Table 1
988H Hydraulic Fan Pump Pressure
Date Equipment ID Code
Pump Pressure Setting Actual
Margin Pressure 3000 100 kPa (435 15 psi) Introduction
The hydraulic fan pump is a variable displacement piston pump that is pressure compensated and flow compensated. The pump control valve controls cutoff pressure of the piston pump. Also, the pump control valve controls the margin pressure of the piston pump. The margin pressure is the difference between the output pressure of the pump and the signal pressure of the pump. The solenoid valve (demand fan) varies the control signal to the pump. The control signal changes the pump output.Measure the margin pressure with the pump swashplate midway between the MAXIMUM OUTPUT position and the MINIMUM OUTPUT position. The Caterpillar Electronic Technician (ET) software must be used in order to override the solenoid valve (demand fan). Caterpillar ET will then provide the correct control pressure to the pump control. The solenoid valve (demand fan) is controlled by the engine ECM.Required Tools
Illustration 1 g03141677
Table 2
Required Tools
Tool Item Qty Part No Description
B1 1 8T-0859 Pressure Gauge
(0 TO 25,000-KPA (0 TO 3,600-PSI))
B2 1 6V-3989 Fitting
B3 2 6V-4143 Quick Connect Coupler
B4 1 1U-5482 Pressure Adapter Group Test Preparation
Before proceeding to the test procedure that follows, complete the procedures:Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".Refer to Testing and Adjusting, "System Pressure Release".Piston Pump Margin Pressure (Hydraulic Fan) - Test
Illustration 2 g03407315
Location of Components of Hydraulic Fan System
(1) Pressure tap for signal pressure
(2) Pump control valve
(3) Hydraulic fan pump
(4) Solenoid valve (demand fan)
(5) Margin pressure adjustment screw
(6) Locking nut
(7) Pressure tap for pump discharge pressure
Attach an unvalved nipple to a 0 to 25000 kPa (0 to 3600 psi) pressure gauge. Attach a hose from 1U-5482 Pressure Adapter Group to the unvalved nipple. Attach the hydraulic line to pressure tap (7).
Attach an unvalved nipple to a 0 to 25000 kPa (0 to 3600 psi) pressure gauge. Attach a section of hydraulic line to the unvalved nipple. Attach the hydraulic line to pressure tap (1).
Engage the parking brake.
Shift the transmission to neutral.
Start the engine. Operate the engine at high idle. Continuously stall the RACK BACK function while simultaneously raising the lift arms at full speed. When the lift arms are almost raised, cycle the tilt cylinder almost to the FULL DUMP position. Then move the tilt cylinders to the full RACK BACK position. Continuously stall the RACK BACK function and simultaneously lower the lift arms back to the ground level position. Without stalling the RACK BACK function, cycle the lift function to raise the lift arms fully. Then lower the lift arms in order to allow the pump to operate at low-pressure briefly and circulate oil through the system. Repeat this process in order to increase the temperature of the oil to normal operating temperature.
Connect Caterpillar ET to the data link connector. The data link connector is next to the keypad. Start Caterpillar ET.
Illustration 3 g03416129
Select "988H". Select "Diagnostics and Diagnostic tests". Select "Override Parameters