| Required Tools | ||
| Part Number | Description | Qty |
| 4C-4892 | ORFS Fittings Group | 1 |
| 9U-7400 | Multitach | 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 bucket and/or attachments 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. |
- Release the pressure from the hydraulic system. For additional information on the hydraulic system pressure release, refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
- Install a 18000 kPa (2610 psi) pressure gauge to pressure tap (1). Pressure tap (1) is located on the discharge line of the pump (2) for the fan drive. The discharge line exits from the top of the fan drive pump. The fan drive pump is mounted to the implement pump (3) .
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| Illustration 1 | g00665270 |
- Install the steering frame lock in the locked position. Start the engine. Engage the parking brake. Lift the blade of the machine several times in order to warm the hydraulic oil.
- Remove the eight bolts that hold the rear grill in place. Remove the rear grill.
- The multitach is used in order to check the speed of the fan. The multitach uses reflective tape and a photo pickup in order to measure the fan speed.
Reference: Refer to Special Instruction, NEHS0605, "9U-7400 Multitach ll Group and 9U-7402 Multitach ll Group" for more information on using the multitach.
- Clean a small area on one of the fan blades. Apply a 50.8 mm (2 inch) strip of 1U-6605 Reflective Tape to the fan blade.
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| Illustration 2 | g00665365 |
A typical example of the installation of the multitach is shown. | |
- Assemble the photo pickup (8) into the clamp on the magnetic base (10). Position the photo pickup in line with the reflective tape. The LED indicator should turn ON as the reflective tape passes by the photo pickup.
Note: The speed of the fan is more important than the oil pressure.
- Start the engine. Be sure that the hydraulic oil is at operating temperature. Run the engine at high idle. Record the reading on the pressure gauge. This pressure represents the setting of the relief valve of the fan pump. The pressure should be approximately 15200 kPa (2204.6 psi).
- Run the engine at high idle and record the speed of the fan from the multitach. The speed of the fan should be approximately 1275 rpm. Stop the engine. Remove the test equipment and install the rear grill if the speed of the fan is within specifications. Proceed to step 10 if the speed of the fan is not correct.
- The relief valve (6) for the fan motor (2) determines the speed of the fan. Loosen locknut (5). Turn adjusting screw (4) clockwise in order to increase the speed of the fan. Turn the adjusting screw counterclockwise in order to decrease the speed of the fan. Tighten locknut (5) .
- Retest the speed of the fan. Adjust the pressure of the relief valve, if necessary.