| Required Tools | ||
| Part Number | Description | Qty |
| 9U-7400 | Multitach | 1 |
| 8T-0859 | Pressure Gauge | 1 |
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Rotating fan blades can result in personal injury or death. Stop the engine and allow the fan to come to a complete stop before making any test or adjustment. Before starting the engine, make sure all of the finger guards are installed securely. Do not allow any tools or test equipment to protrude or vibrate into the path of the rotating fan blades. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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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. |
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| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
- Prepare the machine for service.
Reference: For more information about preparing the machine for service, refer to the Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
- Release the pressure from the hydraulic system.
Reference: For more information about preparing the machine for service, refer to the Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.
- The fan drive pump is attached to the implement pump sections on the right rear side of the flywheel housing. Connect an 8T-0859 Pressure Gauge and a hose assembly to the relief valve pressure tap for the fan drive pump.
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| Illustration 1 | g00291288 |
Location of either the Gear Pump or the Vane Pump for the Hydraulic Fan | |
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| Illustration 2 | g00791735 |
Location of the Pressure Tap on the Fan Pump | |
- Remove eight bolts (1) and grill (2) .
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| Illustration 3 | g00294371 |
- To check the speed of the fan drive motor, a 9U-7400 Multitach must be used. The multitach measures the speed of the fan drive motor by using reflective tape and a photo pickup.
Reference: Special Instruction, NEHS0605, "9U-7400 Multitach II Group and 9U-7402 Multitach II Group"
Note: If a piece of reflective tape is already visible on one of the fan blades, proceed to Step 8. If no reflective tape is visible on one of the fan blades, use the following procedure:
- Remove ten bolts (3) and move lower fan guard (4) in order to access the fan blades.
Show/hide table
Illustration 4 g00292813
The hood has been removed for photographic purposes only.
- Clean a small area on the surface of one fan blade. Position the reflective tape so that the tape is completely visible. Then attach a piece of the tape to the fan blade.
- Install lower fan guard (4). Install bolts (3) and tighten the bolts.
- Place photo pickup (6) into the holder on magnetic base (5) and tighten the screw. Attach magnetic base (5) to the fan guard assembly.
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| Illustration 5 | g00294369 |
Placement of the 9U-7400 Multitach | |
- When the reflective tape and photo pickup (6) are in alignment, the LED indicator (red light) will come on. Position photo pickup (6) accordingly. To check for correct alignment, use a long, narrow object to reach through the fan guard and manually rotate the fan.
Note: When you start the engine, vibration of the machine may cause the photo pickup to become misaligned. It may be necessary to adjust the position of magnetic base (5) in order to realign photo pickup (6) .
- Start the engine. Run the engine at high idle. Move the control levers in all directions in order to warm the hydraulic oil to normal operating temperature (approximately 65°C).
Note: The hydraulic oil must be at normal operating temperature in order to get accurate oil pressure and fan speed results.
- Run the engine at the rated engine speed of 2100 rpm and check the relief pressure for the fan pump. The pressure will vary depending on the pump type.
- 15900 ± 205 kPa (2300 ± 30 psi) for the vane type pump
- 16900 ± 205 kPa (2450 ± 30 psi) for the gear type pump
- 15900 ± 205 kPa (2300 ± 30 psi) for the vane type pump
- Run the engine at the rated engine speed of 2100 rpm and observe the multitach (7). Record the speed of the fan motor.
The speed of the fan motor should be 1450 ± 25 rpm.
Note: Machines that are equipped with a high ambient cooling package are equipped with a gear type pump. Pump relief pressure should be 17306 ± 205 kPa (2510 ± 30 psi). Fan speed for the high ambient cooling package should be 1515 rpm.
- If the speed of the fan motor is not within the specifications, adjust relief valve (8). Use relief valve (8) for the vane pump in order to adjust the fan speed.
Note: If the machine is equipped with a vane pump, then proceed to Step 13.
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| Illustration 6 | g00790459 |
Vane Pump (Hydraulic Fan) | |
Note: If the machine is equipped with a gear pump, then proceed to Step 12.
- If the speed of the fan motor is not within the specifications, adjust relief valve (9). Use relief valve (9) for the gear pump in order to adjust the fan speed.
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| Illustration 7 | g00790460 |
Location of the Relief Valve on the Fan Pump | |
- If any adjustments are made to the fan speed install the pressure gauge and check the pressure of the fan pump.
Note: The speed of the fan drive motor is more critical than the oil pressure. The fan system pressure should not exceed 17750 kPa (2575 psi) for machines that are not equipped with the high ambient cooling package. If the pressure is greater than 17750 kPa (2575 psi) after adjusting the proper speed of the fan motor there is probably a problem with the fan pump or the fan motor.
- Remove all the test equipment. Install the grill (2) and install the eight bolts (1) .
- Before the machine is released into operation, make sure that the oil in the hydraulic tank is at the proper level.