PLATE-CONTROL 1911394 - Caterpillar

The drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the implement and steering pumps.Do not allow personnel into the pump bay area behind the cab when the engine is running.
Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine.To prevent personal injury or death, perform the following:Park the machine on a smooth, level surface.Lower the work tool to the ground and engage the parking brake.Stop the engine and remove the key.Block the wheels and install the steering frame lock.
The hydraulic fan pump is a variable displacement piston pump. There is no pressure relief valve in the hydraulic fan system. The pump control valve controls the pump cutoff pressure. The pump control valve also controls the flow of hydraulic oil to the hydraulic fan motor.
Table 1
Required Tools
Part Number Description
8T-0860(1) Pressure Gauge
6V-3989 Unvalved Nipple
1U-5482 Pressure Adapter Group
(1) The 198-4240 Digital Pressure Indicator is also available.
Illustration 1 g02715974
Pump Compartment
Illustration 2 g06220543
Location of Components of Hydraulic Fan System
(1) Pressure tap for signal pressure
(2a) Pump control valve (Margin Pressure)
(2b) Pump control valve (High Pressure Cut Off)
(3) Hydraulic fan pump
(4) Solenoid valve (demand fan)
(5) Adjustment screw
(6) Locking nut
(7) Pump discharge line
(8) Pump signal lineThe components of the hydraulic fan system are located in the back of the pump compartment.
Prepare the machine for troubleshooting.Reference: For additional information about preparing the machine for troubleshooting, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
Attach an unvalved nipple to a 0 to 40000 kPa (0 to 5800 psi) pressure gauge. Attach a hose from 1U-5482 Pressure Adapter Group to the unvalved nipple. Attach the hydraulic line to the pressure tap on pump control valve (2).
Connect pump discharge line (7) and pump signal line (8) together. Cover the open connections that remain.Note: The demand fan solenoid limits the pump discharge pressure below cutoff of the pump. To ensure that the solenoid does not limit the pump discharge pressure, the discharge pressure must be sent to the signal port of the pump. Discharge pressure that is sent to the signal port of the pump will cause the following. Discharge pressure at the signal port of the pump will cause the fan to run at maximum speed when the engine is at high idle. Discharge pressure at the signal port of the pump will cause the valve for setting the margin pressure to be inoperable and the valve for cutoff pressure will only limit the pump pressure.
Engage the parking brake.
Shift the transmission to neutral.
Start the engine. Warm the hydraulic oil to normal operating temperature of approximately 49 to 65°C (120 to 150°F).
With the engine at high idle, observe the gauge reading.The pump cutoff pressure for machines should be 24000 350 kPa (3480 50 psi).
If the pump cutoff pressure of the hydraulic fan