MH3022, MH3024 and MH3026 Material Handlers Hydraulic System Caterpillar

Specification

Introduction

This procedure verifies that the main pump is operating properly if the maximum displacement of the main pump is adjusted properly.

Prior to performing this test procedure, the following procedure must be performed:

• Check the maximum displacement of the travel motor. Refer to Testing and Adjusting, "Travel Motor (Maximum Displacement) - Test and Adjust" for the machine.

Required Tools

Preliminary Test Procedure

The following test is a rough check for the maximum displacement setting. To perform an exact test of the maximum displacement setting, proceed to "Test Procedure".

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Illustration 1	g03727022
Maximum displacement screw for main pump (MH3022 and MH3024 (FB71-UP))

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Illustration 2	g03858763
Maximum displacement screw for main pump (MH3024 (FM41-UP, FB51-UP) and MH3026)

1. Remove the cap from maximum displacement screw (1).

2. Measure the length of the maximum displacement screw (1) from the end of the maximum displacement screw to the top of the nut. Compare the length to the value in Table 3.

3. Install the cap onto maximum displacement screw (1).

Machine Preparation

1. Clear all personnel from the machine and from the area around the machine.

2. Start the engine.
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   Illustration 3	g02449876
   Engine speed dial

3. Set the engine speed dial at "10".

4. Lower the left console.

5. Position the machine on level ground. Check the visibility and adjust the mirrors for the best vision close to the machine.

6. Fully depress the service brake pedal until the service brake pedal locks mechanically.

7. Increase the hydraulic oil temperature to 46° to 60° C (115° to 140° F).

8. Lower the stabilizers, the blade tip, and/or the implement to raise the front axle and the rear axle. This condition will allow the wheels to turn freely.

   Note: All tires must be fully off the ground.

9. Fully extend the bucket cylinder and place the bucket on the ground.

10. Stop the engine.

11. Release the pressure in the hydraulic system.

    Note: Refer to Testing and Adjusting, "System Pressure - Release".

12. Raise the left console.
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    Illustration 4	g03722485
    Service connector on the right side of cab behind the seat

13. Connect tooling (E) to the service connector.

14. Start the engine.
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    Illustration 5	g02452604

15. Set the engine speed dial at "1".

16. Lower the left console.
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    Illustration 6	g02446738
    Power mode control button on the soft panel switch

17. Push down on the power mode control button to activate power mode.

    Note: The indicator light will be illuminated when power mode is activated.

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    Illustration 7	g02447036
    Automatic Engine Speed Control (AESC) as displayed on the programmable function key in the monitor.

18. Disable the automatic engine speed control through the monitor by pressing the programmable button.
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    Illustration 8	g03722432
    Hydraulic modulation switch on left joystick

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    Illustration 9	g06174873
    Hydraulic modulation medium mode (monitor display)

19. Select the hydraulic modulation mode as medium. Press the lower front switch on the left joystick to select the hydraulic modulation mode.

20. The air conditioning should be turned off for the following test.
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    Illustration 10	g02453444
    Transmission control button on the soft panel switch

21. Push down on the transmission control button to select FIRST GEAR.

    Note: The first indicator light will illuminate when the transmission is in FIRST GEAR.

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    Illustration 11	g02453447
    Creeper speed control button on the soft panel switch

22. Push down on the creeper speed control button to activate the creeper speed control.

    Note: The indicator light will be illuminated when the creeper speed control is activated.

Test Procedure

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

1. Release the service brake pedal.

2. Fully depress the travel pedal.

3. Override the “Main Pump Solenoid Current” until the engine speed has reached the correct value.

   Note: Refer to Table 1 in this manual for the correct value.

   1. Start the Electronic Technician.

   2. Select the Machine ECM and then select “OK”.

   3. Select “Diagnostics” from the main menu.

   4. Select “Diagnostic Tests”.

   5. Select “Override Parameters”.

   6. Select “Travel Pilot Solenoid Current Override” and set the current to 0.8 amp.

   7. Select “Main Pump Solenoid Current” and set the current to 0.4 amp.

   8. Then adjust the “Main Pump Solenoid Current” by 0.2 amp until the “Main Pump Solenoid Current” reaches 1 amp.

      Note: Perform Step 3.h with a fully depressed travel pedal and the bucket in the full Bucket Open position.

4. Verify the engine speed and transmission output speed in Cat ET.

5. Disable all overrides and release the travel pedal.

6. Multiply the engine speed by the calculation factor by the engine speed to get the target transmission output speed.

7. Compare the transmission output speed that was verified in Cat ET with the calculated target shaft speed.

8. If the transmission output speed and the calculated target shaft speed are different, then proceed to the "Adjustment Procedure" to adjust the maximum displacement.

Adjustment Procedure

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

1. Remove the cap from maximum displacement screw (1).

2. If the shaft speed is too high, turn the adjustment screw clockwise to decrease the maximum displacement. If the shaft speed is too low, turn adjustment screw counterclockwise to increase the maximum displacement.

   Note: Always make the final adjustments as the flow increases.

3. While maximum displacement screw (1) is being held, tighten the locknut to the specified torque.

4. Repeat the "Test Procedure" until the target shaft speed has been met.

5. Install the cap onto maximum displacement screw (1).

6. If the test procedure was unsuccessful and transmission output speed and the calculated target shaft speed are not within the specifications, then perform Testing and Adjusting, "Main Pump (Maximum Displacement) - Test and Adjust (Test with Flow Meter)"

   Note: To check the pumps maximum flow, the flow from the main pump will need to be measured with a flow meter.