MH3022, MH3024 and MH3026 Material Handlers Hydraulic System Caterpillar

Introduction

When the main control valve has been serviced or the hydraulic oil has been replaced, use the following procedure to remove air from the hydraulic system:

Machine Preparation

1. Clear all personnel from the machine and from the area around the machine.
   Show/hide table

   NOTICE
   To avoid system damage, make sure that the hydraulic pump is properly filled with hydraulic oil before start-up.

2. Start the engine.
   Show/hide table

   Illustration 1	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. Fully extend the bucket cylinder and place the bucket on the ground.

9. Engage the swing lock pin.
   Show/hide table

   Illustration 2	g02452604
   Engine speed dial

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

Adjustment Procedure

Show/hide table

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.

Show/hide table

Illustration 3	g03721483
Typical example of a main control valve (1) Plug (grapple shock reducing valve) (2) Plug (travel shock reducing valve) (3) Plug (stick shock reducing valve) (4) Plug (stabilizer/dozer shock reducing valve) (5) Plug (boom shock reducing valve)

Show/hide table

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 work tools have been lowered to the ground, 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.

Show/hide table

NOTICE
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.

1. Slowly loosen the plug for the appropriate shock reducing valve.

   Note: Only purge one shock reducing valve at a time

   Note: Apply the service brakes when the air is being removed from the travel control valve.

2. Slowly operate the joysticks for the circuit that is being purged without fully extending the cylinders or without operating at full speed.

3. When oil begins to flow around the plug, tighten the plug for the appropriate shock reducing valve to the specified torque.

4. Repeat Steps 1 through 3 for each circuit.