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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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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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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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| 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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
Introduction
The following procedure is used to adjust the pressure of the main relief valve on the harvester head. Excessive pressure will cause excessive wear on the harvester head.
Adjustment to the base carrier main relief valve is required for this procedure.
ReferenceRefer to the base carrier service manual for the correct adjustment procedure.
The following procedure is used to set the main relief valve on the harvester head.
Required Tools
| Required Tools | ||
| Part | Description | Quantity |
| 8T-5320 | Hydraulic Test Group | 1 |
| 198-4240 | Digital Pressure Indicator Gp | 1 |
| 177-7861 | Hose As | 1 |
Test Procedure
- Prepare the machine for test and adjust procedures. Refer to Testing and Adjusting, "Preparation for Troubleshooting".
- Harvester head in the HORIZONTAL position.
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| Illustration 1 | g02549477 |
The harvester head in the HORIZONTAL position. | |
- Open the valve cover on the harvester head. Disconnect the wire connectors from the tilt valve and the rotator valve if equipped.
- Attach a 0 to 60000 kPa (0 to 8700 psi) pressure gauge to pressure tap (1) (M1) on the inlet block.
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| Illustration 2 | g02406698 |
Main Control Valve | |
- Start the engine. Lower the hydraulic activation control lever. Raise the harvester head approximately 0.3 m (1 ft) above the ground.
- Adjust the base carrier main relief valve to 25000 kPa (3625 psi)
- Set the engine speed to high idle. Activate all close function. Slowly increase the base carrier output pressure to the head by adjusting the base carrier main relief valve. Pressure gauge should max out at 30000 kPa (4350 psi). If pressure is correct go to Step 12. If the pressure needs to be adjusted go to Step 8
- Unlock the set screw on main relief valve (2) (HP). Turn the harvester head main relief valve in one turn to increase the pressure.
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| Illustration 3 | g02406697 |
Main Control Valve | |
- Disconnect the feed forward circuit by unplugging the wire connector from the solenoid.
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| Illustration 4 | g02405756 |
- Set the engine speed to high idle. Activate the forward feed function. Slowly turn in the base carrier main relief valve until the pressure gauge reads 30000 kPa (4350 psi). Turn out the harvester head main relief valve until a hissing sound is heard. Turn the valve back in just until the sound stops. The pressure should now be set at 30000 kPa (4350 psi). Tighten the locknut on main relief valve (2)
- Deactivate the forward feed function. Reconnect the wire connector to the solenoid.
- Lower the harvester head to the ground.
- Shut off the engine. Remove the pressure gauge. Reconnect the wire connectors to the tilt valve and the rotate valve. Close the cover.
- Adjust the main relief valve for the base carrier back to the correct pressure. Refer to base carrier service manual for the correct adjustment procedure.
Worksheet
| HH44DE Main Relief Valve Test and Adjust | ||
|---|---|---|
| Item | Specification | Actual |
| Engine speed | High Idle | |
| Main Relief Valve (HP) | 30000 kPa (4350 psi) |
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