MH3022, MH3024 and MH3026 Material Handlers Hydraulic System Caterpillar

Specification

Introduction

This procedure is utilized to test the case drain pressure for the main pump.

Required Tools

Illustration 1	g01623868
Tooling (B) 198-4240 Digital Pressure Indicator Gp

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 2	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. Lower the stabilizers and the blade tip.

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

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.

13. Attach tooling (F) onto the hydraulic tank. Attach an air supply hose onto the assembly. Apply 276 to 414 kPa (40 to 60 psi). This procedure will pull a vacuum on the hydraulic system.
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    Illustration 3	g03856539
    Right side view of main pump (typical example) (1) Tank (2) Case drain filter (3) Test port for case drain pressure

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    Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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    NOTICE
    Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. 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 in Caterpillar machines. Dispose of all fluids according to local regulations and mandates.

14. Install tooling (G1) adapter into test port (3) for the case drain pressure on the main pump and install fitting assembly (G2) into adapter (G1).

15. Remove tooling (F) and install the filler plug for the hydraulic tank.

16. Attach tooling (B2) 3,445 kPa (500 psi) pressure sensor to pressure tap (3)

Test Procedure

1. Start the engine.

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

3. Lower the left console.
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   Illustration 4	g02446738
   Power mode control button on the soft panel switch

4. 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 5	g02447036
   Automatic Engine Speed Control (AESC) as displayed on the programmable function key in the monitor.

5. Disable the automatic engine speed control through the monitor by pressing the programmable button.
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   Illustration 6	g03722432
   Hydraulic modulation switch on left joystick

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   Illustration 7	g06174873
   Hydraulic modulation medium mode (monitor display)

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

7. The air conditioning should be turned off for the following test.

8. Operate the implements and check the case drain pressure at test port (3). Refer to Table 1 for the correct pressure.

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.

13. If the pressure at test port (3) does not meet specifications for the case drain pressure, replace case drain filter (1) and repeat the "Test Procedure".