349F and 352F Excavators Hydraulic System Solenoid Valve (Proportional Reducing) - Calibrate - Power Shift Pressure Caterpillar

Introduction

The proportional reducing valve for the power shift pressure is located on the main pump housing. The proportional reducing valve sends the reduced pilot oil pressure to the regulators at the idler pump and the drive pump. The output flow of the idler pump and the drive pump is controlled in accordance with the power shift pressure. Power shift pressure is controlled by the machine ECM.

Preliminary Test

• Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust"

Required Tools

Illustration 1	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

Machine Preparation

1. Position the machine on level ground and stop the engine.

2. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".
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   Illustration 2	g02141625
   Pressure tap for the proportional reducing valve (power shift pressure)

3. Connect a 3447 kPa (500 psi) pressure sensor to the pressure tap for power shift pressure.

Calibration Procedure

1. Start the engine.

2. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

3. Enter the service mode. Input the password "9992".
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   Illustration 3	g02306455

4. Select "Power Shift Pressure" from the "Calibrations" menu.

5. Press the OK key in order to start the calibration. The engine RPM will automatically increase to the equivalence of engine speed dial 10.

6. Confirm the notes on the monitor display. Set up the test conditions in accordance with the instructions. Press the OK key.
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   Illustration 4	g02542459

7. Use the arrows to adjust the pressure until the pressure reading for power shift pressure is at 500 ± 50 kPa (73 ± 7 psi). Press the OK key.
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   Illustration 5	g02542476

8. Use the arrows to adjust the pressure until the pressure reading for power shift pressure is at 2500 ± 50 kPa (363 ± 7 psi). Press the OK key.
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   Illustration 6	g02542496

9. If calibration was successful and no errors occurred, the display will indicate that the calibration is complete.
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   Illustration 7	g02542497

10. The "Error" screen will be displayed on the monitor if an error occurs. The process of calibration will not be saved and the process must be restarted.