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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. |
| Required Tools | ||
| Part Number | Description | Qty |
| 4C-4892 | ORFS Fittings Group | 1 |
| 9U-7400 | Multitach Tool Group | 1 |
- Release the pressure from the hydraulic system. For additional information on the hydraulic system pressure release, refer to Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.
- Fan drive pump (1) is located on the right side of the machine. Connect an 8T-0859 Pressure Gauge or a pressure gauge that is rated at 0 to 24130 kPa (0 to 3500 psi) to pressure tap (2) .
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| Illustration 1 | g00713008 |
Fan Pump (1) Fan drive pump. (2) Pressure tap. | |
- Remove eight bolts (3) and grill (4) .
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| Illustration 2 | g00302989 |
Fan Guard (3) Bolts. (4) Grill. | |
- To check the speed of the fan drive motor, use a 9U-7400 Multitach Tool Group. The multitach can measure the speed of the fan drive motor by using reflective tape and a photo pickup.
Reference: For additional information on the Multitach Group, refer to Special Instruction, NEHS0605, "9U-7400 Multitach II Group and 9U-7402 Multitach II Group".
If a piece of reflective tape is already visible on one of the fan blades, proceed to Step 5. If no reflective tape is visible on one of the fan blades, use the following steps:
Note: Only one piece of reflective tape should be applied to the fan.
- Remove two bolts (5). Remove finger guard assembly (6) .
- Clean a small area on the surface of one fan blade. Position the tape so that the tape is completely visible. Attach 50 mm (2 inch) of 1U-6605 Reflective Tape on the fan blade.
- Install finger guard (6). Install bolts (5) and tighten the bolts.
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| Illustration 3 | g00302991 |
Finger Guard Assembly (5) Bolts. (6) Finger guard. | |
- Assemble photo pickup (9) into the clamp on magnetic base (7). Attach magnetic base (7) to the fan guard assembly.
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| Illustration 4 | g00302992 |
Placement of the 9U-7400 Multitach Tool Group (7) Magnetic base. (8) Multitach. (9) Photo pickup. (10) Fan drive motor. | |
- Position the photo pickup (9) so the reflective tape is aligned with the photo pickup. The LED indicator (red light) turns on when the reflective tape and photo pickup are aligned. To check for correct alignment, use a long, narrow object to reach between the fan guards and manually rotate the fan.
Note: The speed of the fan drive motor is more critical than the oil pressure.
Note: When you start the engine, vibrations and air flow from the fan may cause the photo pickup to become misaligned. It may be necessary to adjust the position of magnetic base (7) in order to align photo pickup (9) .
- Start the engine. Run the engine at high idle. Operate the lift cylinders and the tilt cylinders in order to warm the hydraulic oil. Bring the hydraulic oil up to normal operating temperature.
Note: The hydraulic oil must be at normal operating temperature in order to obtain accurate results.
- Run the engine at high idle and record the reading on the oil pressure gauge. The pressure reading should be equal to the relief valve pressure setting. The pressure should be approximately 13000 kPa (1885 psi).
- Set the fan to the minimum speed setting. Place handle (13) for the ball valve in OPEN position (B) .
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| Illustration 5 | g00713080 |
(11) Adjustment screw for minimum fan speed. (12) Adjustment screw for maximum fan speed. (13) Handle for ball valve. (A) CLOSED position. (B) OPEN position. | |
- Set the engine at low idle of approximately 825 ± 30 rpm. Observe multitach (8) and record the speed of the fan drive motor.
The speed of the fan drive motor should be 470 ± 20 rpm.
- If the speed of the fan drive motor is not within the specifications, adjust the fan speed. Use adjusting screw (11) on the fan drive pump to adjust the minimum fan speed.
Note: Do not overtighten adjusting screw (11) in order to avoid damaging the spool in the pump.
- If the minimum speed for the fan drive motor can not be achieved, adjust the engine idle to the high side of the tolerance range. Then, use adjusting screw (11) on the fan drive pump to adjust the minimum fan speed to 470 ± 20 rpm.
- Set the fan to the maximum speed setting. Place handle (13) for the ball valve in CLOSED position (A) .
- Set the engine at high idle. Observe multitach (8) and record the speed of the fan drive motor.
The speed of the fan drive motor should be 940 ± 20 rpm.
- If the speed of the fan drive motor is not within the specifications, adjust the fan speed. Use adjusting screw (12) on the fan drive pump to adjust the maximum fan speed.
- With the engine at high idle, check the maximum fan speed with handle (13) for the ball valve in OPEN position (B). Observe multitach (8) and record the speed of the fan drive motor.
Note: As the hydraulic system oil gets warmer, the fan speed should increase over the minimum setting. An increase of at least 100 rpm over the minimum setting is expected.
- If the fan speed increases, proceed to Step 18. If the fan speed does not increase, then adjust screw (11) until the fan speed stabilizes. Go to Step 9.
- With the engine at low idle, check the minimum fan speed with handle (13) for the ball valve in CLOSED position (A). Observe multitach (8) and record the speed of the fan drive motor.
Note: The fan speed should increase over the minimum setting. An increase of at least 40 rpm over the minimum setting is expected.
- If the fan speed increases, proceed to Step 21. If the fan speed does not increase, continue with Step 20.
- If the speed of the fan drive motor is not within specifications, then adjust the pressure relief valve on the fan motor.
- Adjust the pressure relief valve on the fan motor in order to correct the fan system pressure and the fan motor rpm. If the fan motor is equipped with an externally adjustable pressure relief valve (14), then the pressure relief setting can be adjusted by using an allen wrench. Loosen locknut (15) and adjust allen head screw (16). One full clockwise turn of the allen head screw will increase the fan speed by approximately 100 rpm. Go to Step 9.
Show/hide table
Illustration 6 g00713335
Note: If the fan motor is not equipped with an externally adjustable pressure relief valve, go to Step 20.b. If the fan motor is equipped with an externally adjustable pressure relief valve, continue with Step 20.a.
- The pressure relief valve must be removed in order to adjust the pressure relief setting. Be careful to not damage the sealing surfaces of the valve. Remove the adapter from the fan motor. Remove the pressure relief valve from the adapter. Spring tension in the pressure relief valve is controlled by a hex head bolt. Fan drive system pressure and fan motor rpm will increase as the spring tension in the pressure relief valve is increased. Insert the relief valve in the adapter. Install the adapter on the fan motor. Tighten the adapter by hand until the adapter is finger tight. Tighten the adapter to 26 ± 4 N·m (19 ± 2 lb ft). Go to Step 9.
- Move handle (13) for the ball valve to OPEN position (B). Stop the engine.
- Remove all test equipment. Install grill (4) and eight bolts (3) .
- Make sure that the hydraulic oil is at the correct level in the hydraulic oil tank before you operate the machine.