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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
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Personal injury can result from contact with hot hydraulic oil and from contact with hydraulic oil that is under high pressure. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. The hydraulic oil pressure must be released before any service on the hydraulic system is performed or serious personal injury could occur. Verify that all of the work tools have been completely lowered to the ground. Release the hydraulic oil pressure at the hydraulic tank through the breaker relief valve when the breaker relief valve is cool enough to touch with your bare hand. Verify that the hydraulic oil is cool before you begin to remove any hydraulic components or hydraulic lines. |
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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, "Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids. Dispose of all fluids according to local regulations and mandates. |
Note: Use the information in the reference to prepare the machine for this test. Also, use the information in the reference to relieve any hydraulic pressure that may be in the hydraulic system.
The procedure requires two people.
ReferenceFor the correct procedure to prepare the machine for this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
ReferenceFor the correct procedure to relieve any hydraulic oil pressure that may be in the hydraulic system, refer to Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.
| Required Tools | ||
| Part Number | Description | Qty |
| 143-6092 | Pressure Differential Meter | 1 |
| 177-7861 | Hose Assembly | 2 |
| 4C-4892 | Fitting Group | 1 |
| 6V-9829 | Cap As | 1 |
| 8T-8902 | Tee | 1 |
| 6V-3965 | Fitting As | 1 |
The margin pressure is the difference between the pump discharge pressure and the load signal pressure.
Travel Pump
- Position the machine on level ground.
- Open the hood for the engine compartment.
 | |
| Illustration 1 | g01162081 |
Switch for the hood | |
 | |
| Illustration 2 | g01069398 |
- Shut off the engine.
- Release all the hydraulic system pressure. See the reference at the start of this procedure for the correct method.
- Attach a 177-7861 Hose Assembly (9) to pressure tap (3) .
 | |
| Illustration 3 | g01390225 |
Main hydraulic pump (1) Travel pump (2) Pressure tap for the load sensing control line (3) Pressure tap for the travel pump (4) Pressure tap for the implement pump (5) Pressure tap for the load sensing control line (6) Implement pump | |
- Attach a 177-7861 Hose Assembly (10) to pressure tap (2) .
- Attach the unconnected end of 177-7861 Hose Assembly (9) to port (channel 1) of the 143-6092 Pressure Differential Meter .
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| Illustration 4 | g01071372 |
- Attach the unconnected end of 177-7861 Hose Assembly (10) to port (channel 2) on the 143-6092 Pressure Differential Meter .
- Start the engine.
- Shift the hydraulic lockout control into the UNLOCKED position. All implements should now be operable.
 | |
| Illustration 5 | g01162712 |
Hydraulic Lockout Control | |
- Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45° C (113° F) to 60° C (140° F).
- Move the engine speed dial to high idle. The high idle speed for the machine that is being serviced is 2250 ± 20 RPM.
- Slowly press the right travel pedal in order to steer the machine to the left.
- Record the margin pressure.
Note: The margin pressure is indicated on the pressure differential meter.
- The reading on the pressure differential meter should be 2500 kPa (360 psi).
- Release the right travel pedal.
- If the margin pressure is not correct, an adjustment to adjustment screw (11) for the margin pressure must be made. The adjustment screw for the margin pressure is located on the main hydraulic pumps.
 | |
| Illustration 6 | g01390269 |
Main hydraulic pump (11) Adjustment screw for the travel pump. (12) Adjustment screw for the implement pump. | |
- Move the engine speed dial to low idle. Stop the engine.
- Adjust setscrew (11) in order to adjust the pump margin pressure setting for travel pump (3) . Turn the setscrew clockwise in order to increase the margin pressure. Turn the setscrew counterclockwise in order to decrease the margin pressure.
- Repeat Steps 12 through 19 until the margin pressure is correct.
- Relieve the hydraulic pressure. See the reference at the start of this procedure for the correct method .
- Remove all the hydraulic test equipment. Connect all the lines.
Implement Pump
- Position the machine on level ground.
- Open the hood for the engine compartment.
| | |
| Illustration 7 | g01162081 |
The switch for the hood | |
| | |
| Illustration 8 | g01069398 |
- Shut off the engine.
- Release all the hydraulic system pressure. See the reference at the start of this procedure for the correct method .
- Attach a 177-7861 Hose Assembly (9) to pressure tap (4) .
 | |
| Illustration 9 | g01390272 |
Main hydraulic pump (1) Travel pump (2) Load sensing line from travel valve (3) Pressure tap for travel pump (4) Pressure tap for implement pump (5) Load sensing line from implement valve (6) Implement pump | |
- Attach a 177-7861 Hose Assembly (10) to pressure tap (5) .
- Attach the unconnected end of 177-7861 Hose Assembly (9) to port (channel 1) of the 143-6092 Pressure Differential Meter .
| | |
| Illustration 10 | g01071372 |
- Attach the unconnected end of 177-7861 Hose Assembly (10) to port (channel 2) of the 143-6092 Pressure Differential Meter .
- Start the engine.
- Shift the hydraulic lockout control into the UNLOCKED position. All the implements should now be operable.
| | |
| Illustration 11 | g01162712 |
Hydraulic Lockout control | |
- Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45° C (113° F) to 60° C (140° F).
- Move the engine speed dial to high idle.
- Slowly move the right joystick in order to raise the boom.
- Record the margin pressure.
Note: The margin pressure is indicated on the pressure differential meter.
- The reading on the pressure differential meter should be 2500 kPa (360 psi).
- Lower the boom to the ground.
- If the margin pressure is not correct, an adjustment to adjustment screw (12) for the margin pressure must be made. The adjustment screw for the margin pressure is located on the main hydraulic pumps.
 | |
| Illustration 12 | g01390273 |
Main hydraulic pump (11) Adjustment screw for the travel pump. (12) Adjustment screw for the implement pump. | |
- Move the engine speed dial to low idle. Stop the engine.
- Adjust setscrew (12) in order to adjust the pump margin pressure setting for implement pump (4) . Turn the setscrew clockwise in order to increase the margin pressure. Turn the setscrew counterclockwise in order to decrease the margin pressure.
- Repeat Steps 12 through 19 until the margin pressure is correct.
- Relieve the system hydraulic pressure. See the reference at the start of this procedure for the correct method .
- Remove all the hydraulic test equipment.