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 for approximately five minutes. Cycle the boom and the stick.
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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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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| 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, "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.
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| Illustration 1 | g00357636 |
Harvester Head in the TROUBLESHOOTING Position | |
- Place blocks in front of the wheels. Place blocks behind the wheels.
- 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.
- Install the steering frame lock so that the machine can not articulate. Install the lock pin in order to prevent rotation of the cab.
- Turn the attachment switch 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 attachment switch to the ON position. Move the control levers through the full range of travel.
- Turn the attachment switch to the OFF position. Turn the engine start switch to the OFF position.
- Turn the battery disconnect switch to the OFF position.
- In order to relieve all of the pressure in the hydraulic oil tank, depress the vacuum relief valve.
- Unfasten buckles (3). Remove nuts (2). Unfasten latches (1) .
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| Illustration 2 | g00453840 |
Valve Cover on a HH75 Harvester Head (1) Latch. (2) Nut. (3) Buckle. | |
- Slide the valve cover off the harvester head.
Note: The valve cover on the HH45, HH55, and HH65 weighs approximately 15.9 kg (35 lb). The valve cover on the HH75 weighs approximately 29.5 kg (65 lb). Use two people to remove the valve cover on a HH75.
- In order to relieve the oil pressure in the harvester head, attach a wrench to one of the studs on the valve. The studs are shown in Illustration 3. Slowly turn the wrench until the wrench is fully down. Slowly turn the wrench until the wrench is fully up.
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| Illustration 3 | g00429560 |
Left Side of the Hydraulic Control Valve on a HH65 Harvester Head | |
- Repeat step 13 for each stud on the hydraulic control valve. The HH45 Harvester Head, HH55 Harvester Head, and HH65 Harvester Head have seven studs. The HH75 Harvester Head has eight studs.
- Make sure that all oil pressure is released before you begin any work on the electrohydraulic system.