314D Excavator Hydraulic System Caterpillar

Test

1. Position the machine on level ground.

2. Stop the engine.

3. Release the pressure in the hydraulic system. For more information, refer to Testing and Adjusting, "Hydraulic System Pressure - Release".

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Illustration 1	g01516004
Pump compartment (1) Pressure tap (delivery pressure for drive pump) (2) Pressure tap (delivery pressure for idler pump) (3) Pressure tap (power shift pressure)

4. Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (1) .

5. Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (2) .

6. Connect a 6000 kPa (870 psi) pressure gauge to pressure tap (3) . This is used to monitor power shift pressure.

7. Start the engine.

8. Place the machine controls at the following settings: engine speed dial 10 and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.

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

10. Enter the Service Mode and set the power shift pressure to the specification. Refer to Table 1 for the pressure specification.

    ReferenceRefer to Testing and Adjusting, "Relief Valve (Line) - Test and Adjust".

11. Refer to Table 1 for the pressure settings of the stick cylinder.
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    Table 1

    Relief Valve Pressure Settings
    Cylinder	Cylinder Position	Power shift Pressure and Engine Speed (1)	Relief Pressure Setting
    			Standard	Power Offset Boom
    Stick	Extended	2900 ± 50 kPa (421 ± 7 psi) Engine speed dial "10"	32500 + 1500 - 500 kPa (4714 + 218 - 73 psi)	31900 + 1500 - 500 kPa (4627 + 218 - 73 psi)
    	Retracted	2900 ± 50 kPa (421 ± 7 psi) Engine speed dial "10"	32500 + 1500 - 500 kPa (4714 + 218 - 73 psi)	31900 + 1500 - 500 kPa (4627 + 218 - 73 psi)

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    ( 1 )

    AEC switch OFF

Adjustment (Stick Cylinder Rod End)

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Illustration 2	g01444904
Cutaway view of stick lowering control valve (4) Relief valve (5) Locknut (6) Adjustment screw

1. Mark the location of adjustment screw (6) on relief valve (4) .

   Note: The stick lowering control valve is located on the stick cylinder.

2. To adjust the line relief valve pressure setting of the stick cylinder rod end, move the joystick for the stick until the stick is at full STICK OUT position (full retraction of stick cylinder). Hold the joystick for the stick in this position.

3. Check the pressure in the stick cylinder rod end on the pressure gauge at pressure tap (2) .

4. Return the joystick for the stick to the NEUTRAL position.

5. If the pressure gauge reading at pressure tap (2) is not within the specification, adjust line relief valve (4) that is on the stick lowering control valve.

6. In order to adjust line relief valve (4) , loosen locknut (5) and turn adjustment screw (6) until the pressure gauge reading at pressure tap (2) is within the specification.

   Note: Turn the adjustment screw clockwise in order to increase the pressure. Turn the adjustment screw counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

7. Tighten locknut (5) to a torque of 29 ± 2 N·m (22 ± 2 lb ft).

Adjustment (Stick Cylinder Head End)

1. To adjust the line relief valve pressure setting of the stick cylinder head end, move the joystick for the stick until the stick is at the full STICK IN position (full extension of stick cylinder). Hold the joystick for the stick in this position.

2. Check the pressure in the stick cylinder head end on the pressure gauge at pressure tap (2) .

3. Return the joystick for the stick to the NEUTRAL position.

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Illustration 3	g02093833
Line relief valve (typical example) (7) Relief valve (8) Locknut (9) Adjustment screw

4. If the pressure gauge reading at pressure tap (2) is not within the specification, adjust line relief valve (7) that is on the main control valve.

5. In order to adjust line relief valve (7) , loosen locknut (8) and turn adjustment screw (9) until the pressure gauge reading at pressure tap (2) is within the specification.

   Note: Turn the adjustment screw clockwise in order to increase the pressure. Turn the adjustment screw counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

6. Tighten locknut (8) to a torque of 29 ± 2 N·m (22 ± 2 lb ft).