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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting". |
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Refer to the Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting". Also, refer to the Systems Operation, Testing and Adjusting, "Visual Inspection" section before you attempt any troubleshooting procedures. The item numbers that are used in this topic are the same item numbers that are used in Systems Operation, "Pilot Hydraulic System".
Problem
The hydraulic pump is noisy.
Possible Causes
- The hydraulic oil level is low. Refer to Operation and Maintenance Manual, SEBU7371, "Hydraulic System Oil Level - Check".
- Air in the hydraulic circuit
- Worn pump
- Loose connection at the oil pump inlet
- Oil viscosity is incorrect. Refer to Operation and Maintenance Manual, SEBU7371, "Lubricant Viscosities and Refill Capacities".
Problem
The implements are jerky or the cylinder rods are sticking.
Possible Causes
- The hydraulic oil level is low. Refer to Operation and Maintenance Manual, SEBU7371, "Hydraulic System Oil Level - Check".
- Air in the hydraulic circuit
- Worn pump
- Loose connection at the oil pump inlet
- Oil viscosity is incorrect. Refer to Operation and Maintenance Manual, SEBU7371, "Lubricant Viscosities and Refill Capacities".
Problem
All implements and steering are inoperative.
Possible Causes
- Faulty relief valve for the bank valve
- Fault in the pump control system
- Pump failure. Refer to Disassembly and Assembly, RENR3437, "Hydraulic Pump".
- Failure to the pump drive
- Blocked resolver network for the bank valve
Problem
All implements are inoperative except the auxiliary actuator, frame level, stabilizers, and the steering.
Possible Cause
- Low pilot pressure. Refer to Systems Operation, Testing and Adjusting, "Pilot Hydraulic System".
Problem
An auxiliary actuator fails to operate.
Possible Causes
- Electrical fault in control circuit
- The solenoids that operate the implement section of the bank valve are faulty. Refer to Systems Operation, Testing and Adjusting, "Auxiliary System".
Problem
One or more of the implements does not operate.
Possible Causes
- Low standby pressure
- The resolver network of the bank valve is faulty. Refer to Systems Operation, Testing and Adjusting, "Pilot Hydraulic System".
- The load control valve on the implement cylinder is faulty.
Problem
The frame leveling cylinder does not operate.
Possible Causes
- Electrical fault in control circuit
- Faulty load control valve on the frame leveling cylinder
- Damaged frame leveling cylinder
.
Problem
Movement of the boom or work tool is erratic.
Possible Causes
- Hydraulic system oil level is low. Refer to Operation and Maintenance Manual, SEBU7371, "Hydraulic Oil Level Check".
- Air in hydraulic oil
- The output from the pump is not constant.
- Pressure in the signal line from the bank valve is erratic due to dirt in the resolver network.
- The work tool is faulty or the load control valve for the cylinder is faulty.
- Dirty oil is affecting the metering action of the joystick control.
Problem
The quick coupler fails to maintain the selected angle when the boom is raised or lowered.
Possible Causes
- There is leakage past the seals for the compensating cylinders or past the seals for the tilt cylinder. Refer to Systems Operation, Testing and Adjusting, "Tilt System".
- Leakage past the check valves or the relief valves for the compensating cylinders or the tilt cylinder
Problem
Due to drift of one or more of the boom cylinders, the quick coupler fails to hold the position that was desired.
Possible Causes
- The cylinder has internal leakage due to cylinder damage or wear.
- The load control valve on the cylinder has leakage due to damage or wear.
Problem
Movement of the quick coupler or the boom extend/retract is slow or inoperative.
Possible Cause
- Filter screens in control valve (4) or control valve (14) are blocked.
- The load control valve for the telescoping cylinder is faulty or the load control valve for the quick coupler is faulty.
Problem
The boom does not extend.
Possible Causes
- Filter screens in control valve (4) or control valve (14) are blocked.
- The resolver network of the bank valve is faulty.
- Resolver valves in the control valve (access platform) are faulty.
- The filter screens in the control valve (access platform) are blocked.
- The solenoid valve for the boom extend in control valve (4) or control valve (14) are not activated due to sticking or an open electrical circuit.
- The load control valve for the telescoping cylinder is faulty.
Problem
The boom does not retract.
Possible Causes
- Filter screens in control valve (4) or control valve (14) are blocked.
- The resolver network of the bank valve is faulty.
- The solenoid valve for the boom retract in the control valve (access platform) is not activated due to sticking or an open electrical circuit.
- The load control valve for the telescoping cylinder is faulty.
Problem
The quick coupler does not tilt forward.
Possible Causes
- Solenoid valve (5) or solenoid valve (6) in control valve (4) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- Solenoid valve (11) or solenoid valve (12) in control valve (14) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- The load control valve for the tilt cylinder is faulty.
- The resolver network for the bank valve is faulty.
- The relief valve for the coupler tilt is faulty.
- Filter screens in control valve (4) or control valve (14) are blocked.
Problem
The quick coupler does not tilt back.
Possible Cause
- Solenoid valve (7) in control valve (4) is not activated due to sticking or the solenoid valve has an open electrical circuit.
- . Solenoid valve (9) or solenoid valve (10) in control valve (14) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- The load control valve for the tilt cylinder is faulty.
- The resolver network for the bank valve is faulty.
- The relief valve for the coupler tilt is sticking open.
- Filter screens in control valve (4) or control valve (14) are blocked.
Problem
The boom extends when the tilt forward for the quick coupler is selected.
Possible Cause
- Solenoid valve (6) in control valve (4) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- Solenoid valve (12) in control valve (14) is not activated due to sticking or the solenoid valve has a open electrical circuit.
Problem
The boom retracts when the tilt back for the quick coupler is selected.
Possible Cause
- Solenoid valve (7) in control valve (4) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- Solenoid valve (10) in control valve (14) is not activated due to sticking or the solenoid valve has a open electrical circuit.
Problem
The controls for the access platform are inoperative.
Possible Causes
- Failure of electrical power supply to access platform
- The solenoid valve for boom speed or the selector solenoid valve in the control valve (access platform) is not activated due to sticking or the solenoid valve has a open electrical circuit.
- Blocked filter screen at the pilot pressure inlet of the control valve (access platform)
- Faulty resolver valve in the control valve (access platform)
- Faulty shuttle valves in the control valve (access platform) due to dirt contamination which causes internal leakage to the hydraulic tank
Problem
The boom functions of the joystick control and the control of the access platform are inoperative.
Possible Causes
- The solenoid valve for boom speed or the selector solenoid valve in the control valve (access platform) is sticking.
- The filter screen at the pilot pressure inlet of the control valve (access platform) is blocked.
- The filter screen at the pilot pressure outlet of the control valve (access platform) is blocked.
- The pilot pressure from the bank valve is incorrect.
Problem
One or more boom functions at the controls for the access platform are inoperative.
Possible Causes
- Failure of the solenoid valves (implement control) in the control valve (access platform) due to open circuit or sticking
- Faulty cable drum
Problem
Boom functions are slow or uneven at the control for the access platform.
Possible Causes
- Contamination or corrosion in the cable drum
- The pressure reducing valve or the solenoid valve for boom speed in the control valve (access platform) is sticking.
- There is dirt in the resolver valve network of the control valve (access platform).