M313C, M315C, M316C, M318C and M322C Excavators and M318C and M322C Material Handlers Hydraulic System Caterpillar

Note: The margin pressure must be correct before checking and adjusting the main control valve.

Machine Preparation

1. Start the engine.

2. Lower the left console.

3. Position the machine on level ground.

4. Stop the engine.

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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 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 Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

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Illustration 1	g01206478
The remote pressure taps are located behind the left rear access door. (1) Pressure tap (Main pump pressure) (2) Pressure tap (Proportional reducing valve pressure (Main pump))

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Illustration 2	g00293506
Tooling for the Main Pump (3) Pressure tap (Destroking pressure)

5. Connect a 60000 kPa (8600 psi) pressure gauge to pressure tap (1) .

6. Connect a 4000 kPa (580 psi) pressure gauge to pressure tap (2) .

7. Connect a 25000 kPa (3600 psi) pressure gauge to pressure tap (3) .

Test and Adjust

1. Start the engine.

2. Lower the left console.

3. Adjust the engine speed to HIGH IDLE by turning the engine speed dial to position 10.

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Illustration 3	g01257986
Main Control Valve ( M313C, M315C, and M316C) (4) Locknut (5) Adjustment screw (Main relief valve pressure)

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Illustration 4	g01206479
Main Control Valve ( M318C, M318C MH, M322C, and M322C MH) (4) Locknut (5) Adjustment screw (Main relief valve pressure)

4. Loosen locknut (4) on the main relief valve.

5. Turn adjustment screw (5) by three full turns counterclockwise.

6. Move the right joystick to the full BUCKET CLOSE position until the cylinder is fully extended.

   Note: Stall the bucket in the BUCKET CLOSE position.

7. Turn adjustment screw (5) clockwise and watch the pressure gauge on pressure tap (1). Continue turning the adjustment screw clockwise until the pressure is 10000 kPa (1450 psi).

   Note: The pressure at pressure tap (3) should be 0 to 500 kPa (0 to 73 psi).

8. While the engine is running, maintain the power shift pressure at a constant pressure. Use the following procedure to obtain the constant power shift pressure:
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   Illustration 5	g00917706
   Right Side of Cab Seat (6) Service tool connector

   1. Connect the Electronic Technician (ET) to service tool connector (6) of the machine.

   2. Start Electronic Technician.

   3. Select the "Engine ECM" from the list of available controls.

   4. Select "OK".

   5. Select "Diagnostics" from the main menu.

   6. Select "Diagnostic Tests".

   7. Select "Override Parameters".

   8. Select "Main Pump Power Shift Pres Sol Current Override".
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   Illustration 6	g00918489
   ET (Diagnostic Override Screen)

   9. Select the "Change" button.

   10. Enter a current value of "0".

   11. Select "OK".

   12. Select "Yes".

   13. Select the "Change" button.
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       Table 2

       Main Pump Destroke Pressure At Mode P
       Machine Model	Reference Current Value (Ampere)
       M313C	0.540
       M315C	0.570
       M316C	0.600
       M318C and M318C MH	0.540
       M322C and M322C MH	0.550

   14. Enter a current value in order to set the "Mode P" pressure for the main pump (proportional reducing valve). Start with the reference current value that is shown in Table 2 for your machine. Refer to Testing and Adjusting, "Specifications" in this manual for the correct "Mode P" pressure for the main pump (proportional reducing valve).

       Note: You must first enter a current value of "0" whenever you are changing the existing current value.

   15. Select "OK".

   16. Select "Yes".

   17. Check the pressure at pressure tap (2) .

   18. Repeat Steps 8.m through 8.q until the correct pressure is reached.

9. Move the right joystick to the full BUCKET CLOSE position until the cylinder is fully extended.

   Note: Stall the bucket in the BUCKET CLOSE position.

10. Adjust the main relief valve in order to increase the main pump pressure at pressure tap (1) .

    Refer to Testing and Adjusting, "Specifications" in this manual for the correct destroke pressure at "Mode P" for your machine. When the main pump destroke pressure at pressure tap (1) is set to the correct pressure, there should be a sudden pressure increase at pressure tap (3). Pressure at pressure tap (3) should be approximately 1/3 of the main pump pressure at pressure tap (1) .

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Illustration 7	g01206483
Pump Compartment (7) Destroke pressure

11. If the destroke pressure is not within specifications, proceed to the next step.

12. Stop the engine.

13. Remove the cap and loosen the locknut on the adjustment screw for destroke pressure (7) .

14. Turn the adjustment screw in order to adjust the pressure setting. Turning the adjustment screw clockwise increases the pressure setting. Turning the adjustment screw counterclockwise decreases the pressure setting.

15. Start the engine.

16. Turn the adjustment screw for destroke pressure (7) until a sudden increase in pressure occurs at pressure tap (3). The increase in pressure should occur when the main pump pressure is 14000 to 16000 kPa (2030 to 2320 psi). Refer to Testing and Adjusting, "Specifications" in this manual for the correct "Mode P" pressure for destroke for your machine.

17. Tighten the locknut to the specified torque.

18. Select the "Disable Override" button in ET.

19. Reset the main relief valve pressure. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".