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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. |
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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.
| Required Tools | |
| Part Number | Description |
| 8T-0860(1) | Pressure Gauge |
| (1) | The 198-4240 Digital Pressure Indicator is also available. |
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| Illustration 1 | g01446244 |
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Location of pressure tap for fan pump discharge in pump compartment | |
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| Illustration 2 | g01446333 |
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Hydraulic fan pump for standard ambient temperature cooling (view from drive end) Location of adjustment screw for cutoff pressure | |
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| Illustration 3 | g01446347 |
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Hydraulic fan pump for high ambient temperature cooling Location of adjustment screw for cutoff pressure | |
- Prepare the machine for troubleshooting.
- Attach 8T-0860 Pressure Gauge to the pressure tap for fan pump discharge. Refer to Illustration 1.
- 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) . - Connect Caterpillar ET to the data link connector. The data link connector is on the control panel on the right side of the cab. Start Caterpillar ET.
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Illustration 4 g01446423 - Select "C32 993K". Select "Diagnostics". Select "Diagnostic Tests". Select "Override Parameters".
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Illustration 5 g01446428 - Select "Engine Fan Bypass". Change the value for this parameter to "0%". This should cause the fan to run at maximum speed when the engine is at high idle.
- With the engine at high idle, observe the gauge reading.
The pump cutoff pressure for machines with standard ambient temperature cooling should be
20500 ± 350 kPa (3000 ± 50 psi) .The pump cutoff pressure for machines with high ambient temperature cooling should be
22000 ± 350 kPa (3200 ± 50 psi) . - If the pump cutoff pressure of the hydraulic fan pump is not correct, the cutoff pressure may require an adjustment.
- Stop the engine.
- Loosen the locknut for the adjustment screw for pressure cutoff.
- Turn the adjustment screw clockwise in order to increase the pressure setting. Turn the adjustment screw counterclockwise in order to decrease the pressure setting.
- Tighten the locknut.
- Perform Step 5 through Step 9 of the test procedure again in order to verify the new pressure setting.
- Use Caterpillar ET in order to reset the "Engine Fan Bypass" parameter.
- Exit the Caterpillar ET program and disconnect ET from the machine.
