| REQUIRED TOOLS | |||
| Tool | Part Number | Part Description | Qty |
| A | Test Gauge hose | ||
| 6V-4143 | Coupler (1) | 1 | |
| 177-7860 | hose Assembly (1) | 1 | |
| 8T-4188 | Union Adapter (1) | 1 | |
| 6V-3966 | Fitting (1) | 1 | |
| B | Test Gauge | ||
| 8T-0861 | Pressure Gauge (1) | 1 | |
| 6V-4144 | Coupler (1) | 1 | |
| ( 1 ) | Part of 4C-4892 ORFS Fittings Group |
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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 work tools have been lowered to the ground, and the 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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| NOTICE |
|---|
The lift line relief pressure is set higher than the main relief pressure. Do not increase the main relief pressure setting in order to check the lift line relief pressure setting. Damage to the hydraulic system may occur. |
| Pressure for line relief Valve | ||
| Model | Implement Valve Function | Pressure |
| 834G Wheel Tractor | Lift Pressure for Rod End Line Relief | 34500 ± 1500 kPa (5000 ± 200 psi) |
| 834G Wheel Tractor | Pressure for Tilt and Tip Line Relief | 25000 ± 1500 kPa (3600 ± 200 psi) |
| 836G Landfill Compactor | Lift Pressure for Rod End Line Relief | 27000 ± 1500 kPa (4000 ± 200 psi) |
Machine Preparation
Prepare the machine for testing by completing the procedure that is specified in the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
Location of the Relief Valve
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| Illustration 1 | g00747530 |
Main Control Valve for the 834G Wheel Tractor (1) Head end line relief valve for the tip cylinder. (2) Rod end line relief valve for the tip cylinder. (3) Main relief valve. (4) Rod end line relief valve for the tilt cylinder. (5 ) Rod end line relief valve for the lift cylinder | |
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| Illustration 2 | g00741139 |
Main Control Valve for the 836G Landfill Compactor (6) Rod end line relief valve for the lift cylinder | |
Rod End Line Relief Valve for the Lift Cylinder
- The lift pressure for the rod end line relief valve for the 834G Wheel Tractor and the 836G Landfill Compactor is set higher than the main relief valve. No adjustments for the rod end line relief valve can be made in this case. If the lift function of the cylinder is slow, then perform the following tests. Also, if the lift function does not respond to the control levers perform the following tests.
- Ensure that there is a signal voltage at the lift solenoid assembly. Ensure that the lift solenoid assembly is operational.
- Ensure that the work tool can be lowered.
- Check that the lift cylinder does not drift.
- Ensure that the main relief valve is adjusted properly.
- Ensure that the tip and tilt cylinder are operational.
If the above items are functioning properly, then replace rod end line relief valve (6) for the 834G Wheel Tractor. If the above items are functioning properly, then replace rod end line relief valve (7) for the 836G Landfill Compactor.
- Ensure that there is a signal voltage at the lift solenoid assembly. Ensure that the lift solenoid assembly is operational.
Line Relief Valves for the Tip and Tilt Cylinders ( 834GWheel Tractor)
- Start the machine.
- Lower the work tool to the ground.
- Stop the engine.
- Connect test gauge (B) to test gauge hose (A). Install test gauge hose (A) on pressure tap (8) .
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| Illustration 3 | g00726269 |
Implement Pump (8) Pressure tap for line relief pressure | |
- Start the engine. Increase the engine speed to high idle. In order to increase the temperature of the hydraulic oil to normal operating temperature, operate the implement control levers.
- Raise the work tool off the ground. In order to test the line relief (1), operate control lever (8) and move the work tool to full tilt left. Record the pressure on gauge (B). In order to test line relief (2), operate control lever (8) and move the work tool to the full tip back. Record the pressure on gauge (B). In order to test line relief (4), operate control lever (8) and extend the tip cylinder to the end of the cylinder stroke. Move the rocker switch (9) to the tilt function and move the tilt cylinder to full tilt right with control lever (8) .
Note: The blade is in the tilt left position when the left side of the blade is lower than the right side of the blade. The blade tilt angle is seen from the cab seat.
Note: Do not hold the relief valve pressure for more than 30 seconds.
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| Illustration 4 | g00742589 |
Hydraulic Electric Control in the Cab (8) Control lever. (9) Implement function selection switch for the 834G Wheel Tractor. (10) Implement lockout switch. | |
- If the recorded pressure is equal to the listed pressure in the Table 2, then lower the work tool to the ground. Shut off the engine. If the recorded pressure is not equal to the pressure in Table 2 proceed to Step 9.
- Remove the cover (11) for the implement control valve. Loosen locknut (13) for the line relief valve that is being adjusted. Rotate adjustment screw (12) counterclockwise if the pressure must be reduced. Rotate adjustment screw (12) clockwise if the pressure must be increased. Hold adjustment screw (12) and tighten locknut (13) after the adjustment screw is rotated.
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| Illustration 5 | g00741013 |
(11) Main Control Valve Cover | |
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| Illustration 6 | g00741062 |
Relief Valve (12) Adjustment screw. (13) Locknut | |
- After each adjustment, check the line relief pressure. Continue to adjust the line relief valve in order to reach the desired relief pressure setting.
- After the line relief pressure is adjusted, hold the adjustment screw (12) and tighten the jam nut (13) to 50 N·m (35 lb ft).
- Remove the test gauge hose (A) and test gauge (B) from the machine.
- Install the cover (11) for the implement control valve.