For any test to the electrohydraulic system, the hydraulic oil must be at the normal operating temperature. To increase the oil temperature, start the engine. Operate the feed rollers until the oil temperature is approximately 50° C (120° F). Cycle the boom, the stick and all of the functions of the harvester head.
Before any tests are performed, visually inspect the complete electrohydraulic system for oil leaks and for damaged parts. Also, visually inspect the wiring connectors and wiring harnesses for damage and for corrosion. Verify that the wiring connectors are making good contact.
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Sudden movement of the tilt cylinders and/or rotator is possible if the tilt and rotate functions are not disconnected. Sudden movement of the tilt cylinders and/or rotator could result in serious injury or death. When checking and/or adjusting any of the harvester head pressures, the tilt circuit solenoids must be disconnected. If equipped, the rotate circuit solenoids must also be disconnected. |
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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. |
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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
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It is possible for the frame of the harvester head to fall when it is parked in the vertical position. To avoid personal injury or death and equipment damage, wrap a chain around one leg of the frame and one leg of the yoke. Secure the chain in an appropriate manner. |
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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. |
- Permit only one operator on the machine. Keep other personnel away from the machine and the harvester head.
- Move away from other operating machines and away from personnel. Park the machine on a smooth, level surface. Tilt the harvester head into the HORIZONTAL position. Lower the harvester head to the ground. If the troubleshooting procedure requires the harvester head to be in the VERTICAL position, secure the C-frame to harvester head with a suitable chain. Refer to Figure 2
Note: Wheel machines need blocks place in front and behind the wheels. Install steering frame lock. Install the lock pin to prevent the cab from rotating.
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| Illustration 1 | g02549477 |
The harvester head in the HORIZONTAL position. | |
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| Illustration 2 | g02407516 |
The harvester head in the VERTICAL position. | |
- Remove the saw chain and the saw bar before performing any troubleshooting procedures.
- When the harvester head is raised for testing or for adjusting, do not allow personnel under the harvester head or near moving components. The boom circuit and the stick circuit have high oil pressure when the harvester head is off the ground.
- Turn the switch for the computer aided bucking system (CABS) to the OFF position. Stop the engine by turning the engine start switch key to the OFF position.
- Turn the engine start switch to the ON position. Do not start the engine. Turn the switch for the computer aided bucking system (CABS) to the ON position.
- Place the hydraulic activation control lever in the UNLOCKED position.
- Move the joysticks and the pedals of the hydraulic circuit to the FULL STROKE positions. This action will release the high pressure in the hydraulic circuit. This action will also release any pressure that might be present in the pilot hydraulic circuit.
- Place the hydraulic activation control lever in the LOCKED position.
- Turn the switch for the computer aided bucking system (CABS) to the OFF position. Turn the engine start switch to the OFF position.
- Slowly loosen the filler plug on the hydraulic tank and release the pressure from the hydraulic tank. Leave the filler plug loose for a minimum of 45 seconds. This action will release the pressure that may be present in the return hydraulic circuit.
- Tighten the filler plug on the hydraulic tank to the specified torque.
- The pressure in the multiple hydraulic circuits that require service is now released and lines and components can be disconnected or removed from those hydraulic circuits.
- Make sure that all oil pressure is released before you begin any work on the harvester head.
- Open the valve cover on the harvester head.
- Disconnect wire harnesses (1) and (2) that connects to the valve section for tilt cylinders (3). If equipped, disconnect wire harnesses (4) and (5) that connects to the valve section for rotator (6) .
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| Illustration 3 | g02467118 |
Main Control Valve | |