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Personal injury or death can result if two persons are not used in the following procedure. |
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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
| 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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
| 980M/982M Hydraulic Fan Pump Pressure | ||
|---|---|---|
| Date | Equipment ID Code | |
| Pump Pressure | Setting | Actual |
| Margin Pressure (High Idle) | |
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| 980M/982M Torque Specifications | |
|---|---|
| Callout | Torque |
| Locknut (Margin Pressure) (3) | |
This information includes the following test:
- Margin Pressure
This information includes the following adjustment procedure:
- Adjustment Procedure (Margin Pressure)
The fan pump margin pressure is the difference between the fan pump load sense pressure and the fan pump discharge pressure. When a load sense signal is sent to the pump, the controller adds some margin pressure on top of the signal.
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| Illustration 1 | g01879273 |
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Tooling (D) | |
| Tool | Item | Part Number | Description | Qty |
|---|---|---|---|---|
| D | 1U-5796 | Pressure Differential Tool Gp | ||
| D2 | 6V-4143 | Quick Connect Coupler | 4 | |
| D3 | 6V-3965 | Fitting | 3 | |
| D4 | 6V-4144 | Quick Connect Coupler | 1 | |
| D5 | 8T-0859 | Pressure Gauge
(0 to 25,000 kPa (0 to 3,600 psi)) |
1 | |
| D5 | 8T-0861 | Pressure Gauge
(0 to 60,000 kPa (0 to 8,700 psi)) |
1 | |
| D6 | 8C-8431 | Tee | 1 | |
| D7 | 1U-5793 | Oil Filter Pressure Differential Gauge Gp | 1 | |
| D8 | 6V-0484 | O-Ring Adapter | 1 | |
Reference: Refer to Special Instruction, SEHS8979, "Component Identification and Calibration of the 1U5796 Differential Pressure Gauge Group" for more information on using Tooling (D).
Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Refer to Testing and Adjusting, "System Pressure Release".
- Ensure that the hydraulic oil temperature is at least at
60° C (140° F) .Show/hide table
Illustration 2 g03663613 - Move steering frame lock to the LOCKED position.
- Engage the parking brake. Move the transmission direction selector to the NEUTRAL position.
- Release system pressure.
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| Illustration 3 | g03632700 |
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Hydraulic service center. (1) Fan pump discharge pressure tap. (2) Fan pump load sense pressure tap. | |
- Turn off machine and release pressure in system.
Note: The pressure will need to be released out of the system to attach the pressure gauge.
- Attach a
0 to 25000 kPa (0 to 3626 psi) pressure gauge (D5) to the high-pressure port (D4) of pressure differential gauge group (D7). - Attach one end of hydraulic line (D1) to pressure tap (1). Pressure tap (1) is located in the hydraulic service center that is on the right side of the machine. Attach the other end of hydraulic line to the open end of the tee (D6) of pressure differential gauge group (D7).
- Attach another hydraulic line (D1) to the fan pump load sense pressure tap (2). Attach the opposite end of hydraulic line (D1) to the low-pressure port (D8) of the pressure differential gauge group (D7).
Note: Position pressure differential gauge group (D7) and hydraulic lines (D1) in order to prevent damage from any machine movement. Position the test equipment in order to allow a second technician to observe and record the pressure readings safely.
- Record the pressure reading on pressure gauge (D7). The reading that is on pressure gauge (D7) is the margin pressure. Margin pressure is the difference between the fan pump pressure and the load sense pressure (2). The margin pressure should be
1600 ± 100 kPa (232 ± 14 psi) .Note: The pressure reading on pressure gauge (D5) is the fan pump discharge pressure.
- If the margin pressure is correct, turn off the engine, and release the pressure to the hydraulics to disconnect the pressure gauges.
- If the margin pressure is not correct, review the steps in the following section to adjust the pressure.
Adjustment Procedure (Margin Pressure)
- With the engine off, loosen locknut (3) and use an internal hex wrench to adjust the pressure. Turn the adjuster screw clockwise in order to increase the pressure setting. Turn the adjuster screw counterclockwise in order to decrease the pressure setting. One turn of adjustment screw changes margin pressure by approximately
1415 kPa (205 psi) . - After you turn adjustment screw, tighten locknut (3) to a torque of
17 ± 3 N·m (150 ± 26 lb in) . - Turn off the engine off, and release the pressure to the hydraulics to disconnect the pressure gauges.
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| Illustration 4 | g03632879 |
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Hydraulic Fan Pump (3) Adjustment locknut for margin pressure. | |