The back pressure is controlled by a pressure reducing valve. If the pressure is set too high, the feed roller motors will have low feeding force. If the pressure is set too low, the motors could be damaged. Perform the following procedure in order to adjust the back pressure to the feed roller motors.
| Required Tools | ||
| Part | Description | Quantity |
| 8T-5320 | Hydraulic Test Group | 1 |
| 163-0056 | Hose Assembly (1) | 1 |
| ( 1 ) | The hose assembly is not needed for harvester heads that are equipped with Caterpillar pressure taps. |
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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, "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. |
- Prepare the machine for testing and adjusting. Refer to Testing and Adjusting, "Preparation for Troubleshooting".
- Remove the valve cover from the harvester head. Remove the cap from pressure tap (AA). If necessary, attach the adapter to pressure tap (AA). Attach a 0 to 4000 kPa (0 to 580 psi) pressure gauge to pressure tap (AA) or the adapter.
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| Illustration 1 | g00760322 |
Pressure Reducing Valve for Back Pressure (1) Adjustment screw. (2) Locknut. (AA) Pressure tap. | |
- Start the engine. Press the operating mode switch in order to activate the Terrain mode. Turn the engine speed dial until the engine is operating at 1300 RPM. Turn the switch for the computer aided bucking system to the ON position.
- Loosen locknut (2) on the pressure reducing valve. Turn adjustment screw (1) until the pressure gauge indicates 2000 kPa (290 psi).
- Turn the switch for the computer aided bucking system to the OFF position. Press the operating mode switch in order to activate the Neutral mode. Stop the engine.
- Remove the pressure gauge. Remove the adapter if one was installed. Install the dust cap on pressure tap (AA). Install the valve cover.