325C Material Handler Hydraulic System Caterpillar

Note: A temporary setting of the main relief valve pressure is required before any line relief valve pressure setting is adjusted. Refer to the adjustment procedures in Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".

Test

1. Position the machine on level ground.

2. Stop the engine.

3. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".

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Illustration 1	g00940896
Pump compartment (1) Pressure tap (right pump delivery pressure) (2) Pressure tap (left pump delivery pressure) (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, AEC switch OFF and SmartBoom OFF. Refer to Testing and Adjusting, "Engine Performance - Test" for engine rpm settings.

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

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Illustration 2	g00672009
Monitor (A) Message display (B) Keypad (C) Up key (D) Left key (E) Down key (F) Right key (G) Cancel key (H) Set key (I) OK key (J) Menu key

10. Start Service Mode and input a fixed power shift pressure of 2250 kPa (325 psi).

    1. Press menu key (J) .

       Note: If more than thirty seconds pass between pushing the keys on the keypad, the menu mode will be cancelled and the previous display will be restored to message display (A) .

    2. Press down key (E) in order to highlight the menu item "SERVICE OPTIONS" on the message display. Press OK key (I) .

    3. Input the password "FFF2". Press left key (D) or right key (F) in order to change the position of the flashing character. Press up key (C) or press down key (E) in order to change the value of the flashing character. Press OK key (I) after the correct password is displayed.

    4. Press down key (E) once in order to highlight the second line on the message display.

    5. Press right key (F) repeatedly until "DEVICE TEST" appears on the message display.

    6. Press down key (E) in order to move down one line on the message display.

    7. Press right key (F) until the "PS PRV - FIXED" appears on the message display.

    8. Press down key (E) .

    9. Press OK key (I). The display on line 4 of the message display will now change to a numeric value. These characters represent the power shift pressure (kPa).

    10. Press left key (D) or right key (F) in order to increase or decrease the numeric value that is displayed on line 4 of the message display. Pressing left key (D) one time decreases the power shift pressure 10 kPa (1.5 psi). Pressing right key (F) one time increases the power shift pressure 10 kPa (1.5 psi).

        Note: The value for power shift pressure on the monitor may not always match the pressure reading on the pressure gauge. Adjust the value on the monitor until the desired power shift pressure is attained on the pressure gauge that is connected to the pressure tap for power shift pressure. The actual power shift pressure must be 2250 kPa (325 psi) on the pressure gauge.

        Note: To prevent a change in power shift pressure during the relief valve adjustment, do not turn the engine start switch to the OFF position.

        Note: Refer to Service Manual, "Engine and Pump Electronic Control System" for additional information on Service Mode.

11. The pressure setting for both the head end and the rod end for each cylinder is 36800 ± 1500 kPa (5340 ± 220 psi).

Illustration 3	g00949573
Main control valve (front view) (4) Line relief valve (boom cylinder rod end) (5) Line relief valve (rod end of the work tool cylinder) (6) Line relief valve (stick cylinder rod end)

The following line relief valves are located on top of the main control valve: boom cylinder rod end, rod end of the work tool cylinder and stick cylinder rod end. The line relief valve for the head end of the work tool cylinder is located on the bottom of the main control valve and opposite of line relief valve (5) .

The line relief valves for the boom cylinder head ends are located on the boom lowering control valves.

The line relief valves for the stick cylinder head ends are located on the stick lowering control valves.

Adjustment (Boom Cylinder Head End)

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Illustration 4	g00949457
Boom lowering control valve (7) Line relief valve (left boom cylinder head end) (8) Line relief valve (right boom cylinder head end) (9) Adjustment screw (10) Locknut

Note: In order to adjust relief valve (8) on the right boom lowering control valve, relief valve (7) on the left boom lowering control valve must be temporarily adjusted.

1. Mark the location of adjustment screw (9) on relief valve (7) .

2. Loosen locknut (9) on relief valve (7) on the left boom lowering control valve. Turn adjustment screw (9) clockwise by one quarter turn. Tighten locknut (10) .

3. Move the joystick for the boom until the boom is at the full BOOM RAISE position (full extension of boom cylinders). Hold the joystick for the boom in this position.

4. Check the pressure in the boom cylinder head end on the pressure gauge at pressure tap (1) .

5. Return the joystick for the boom to the NEUTRAL position.

6. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (1) is not within the specification, adjust line relief valve (8) .

7. In order to adjust line relief valve (8), loosen locknut (10) and turn adjustment screw (9) until the pressure gauge reading at pressure tap (1) is 36800 ± 1500 kPa (5340 ± 220 psi).

   Note: Turn adjustment screw (9) clockwise in order to increase the pressure. Turn adjustment screw (9) counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

8. Loosen locknut (10) on relief valve (7) on the left boom lowering control valve. Turn adjustment screw (15) counterclockwise by one half turn past the marked position. Tighten locknut (10) .

Note: In order to adjust relief valve (7) on the left boom lowering control valve, relief valve (8) on the right boom lowering control valve must be temporarily adjusted.

9. Mark the location of adjustment screw (9) on relief valve (8) .

10. Turn adjustment screw (9) on relief valve (8) clockwise by one quarter turn. Tighten locknut (10) .

11. Move the joystick for the boom to the full BOOM RAISE position. Hold the joystick for the boom in this position and check the pressure gauge reading at pressure tap (1) .

12. Return the joystick for the boom to the NEUTRAL position.

13. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (1) is not within the specification, adjust line relief valve (7) that is on the left boom lowering control valve.

14. In order to adjust line relief valve (7), loosen locknut (10) and turn adjustment screw (9) until the pressure gauge reading at pressure tap (1) is 36800 ± 1500 kPa (5340 ± 220 psi).

    Note: Turn adjustment screw (9) clockwise in order to increase the pressure. Turn adjustment screw (9) counterclockwise in order to decrease the pressure.

    Note: Always make final pressure adjustment on pressure rise.

15. Tighten locknut (10) on relief valve (7) .

16. Loosen locknut (10) on relief valve (8) on the right boom lowering control valve. Turn adjustment screw (9) counterclockwise by one quarter turn to the marked position. Tighten locknut (10) .

Adjustment (Boom Cylinder Rod End)

Note: In order to adjust the line relief valve pressure setting for the boom cylinder rod end, a temporary adjustment of the line relief valve for the work tool circuit must be performed. Line relief valve (8) for the work tool is located on top of the main control valve.

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Illustration 5	g00949462
Line relief valve (typical example) (11) Adjustment screw (12) Locknut

1. Loosen locknut (12) on the line relief valve for the WORK TOOL CLOSE function. Turn adjustment screw (11) by one half turn in a clockwise direction. Tighten locknut (12) on the line relief valve for the work tool cylinder.

2. Move the joystick for the work tool to the full WORK TOOL CLOSE position (left). Hold the joystick for the work tool in this position. At the same time, move the joystick for the boom until the boom is at the full BOOM DOWN position (full retraction of boom cylinders). Hold the joystick for the boom in this position.

3. Check the pressure in the boom cylinder rod end on the pressure gauge at pressure tap (1) .

4. Return the joystick to the NEUTRAL position.

5. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (1) is not within the specification, adjust line relief valve (4) that is on the main control valve.

6. Loosen locknut (12) on the boom line relief valve. Turn adjustment screw (11) until the pressure gauge reading at pressure tap (1) is 36800 ± 1500 kPa (5340 ± 220 psi).

   Note: Turn adjustment screw (11) clockwise in order to increase the pressure. Turn adjustment screw (11) counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

7. Tighten locknut (12) on the boom line relief valve.

8. After completion of line relief valve adjustment for the boom cylinders, return the line relief valve pressure setting of the work tool to the specified pressure setting.

Note: If an appropriate location is not available to fully extend the boom cylinders, exchange the functions of the boom line relief valves. Remove the line relief valve for the boom cylinder head end and the line relief valve for the boom cylinder rod end from the main control valve. Exchange the location of the line relief valves. Adjust the pressure of the boom line relief valve that is now attached in the head end. After completion of line relief valve adjustment, return the respective line relief valves to the original locations.

Adjustment (Stick Cylinder Head End)

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Illustration 6	g00934570
Stick lowering control valves (13) Line relief valve (left stick cylinder head end) (14) Line relief valve (right stick cylinder head end) (15) Adjustment screw (16) Locknut

Note: In order to adjust relief valve (14) on the right stick lowering control valve, relief valve (13) on the left stick lowering control valve must be temporarily adjusted.

1. Mark the location of adjustment screw (15) on relief valve (13) .

2. Loosen locknut (16) on relief valve (13) on the left stick lowering control valve. Turn adjustment screw (15) clockwise by one quarter turn. Tighten locknut (16) .

3. Move the joystick for the stick until the stick is at the full STICK OUT position (full extension of the stick cylinders). Hold the joystick for the stick in this position.

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

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

6. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (2) is not within the specification, adjust line relief valve (14) .

7. In order to adjust line relief valve (14), loosen locknut (16) and turn adjustment screw (15) until the pressure gauge reading at pressure tap (2) is 36800 ± 1500 kPa (5340 ± 220 psi).

   Note: Turn adjustment screw (15) clockwise in order to increase the pressure. Turn adjustment screw (15) counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

8. Loosen locknut (16) on relief valve (13) on the left stick lowering control valve. Turn adjustment screw (15) counterclockwise by one quarter turn to the marked position. Tighten locknut (16) .

Note: In order to adjust relief valve (13) on the left stick lowering control valve, relief valve (14) on the right stick lowering control valve must be temporarily adjusted.

9. Mark the location of adjustment screw (15) on relief valve (14) .

10. Turn adjustment screw (15) on relief valve (5) clockwise by one quarter turn. Tighten locknut (16) .

11. Move the joystick for the stick to the full STICK OUT position. Hold the joystick for the stick in this position and check the pressure gauge reading at pressure tap (2) .

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

13. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (2) is not within the specification, adjust line relief valve (13) that is on the left stick lowering control valve.

14. In order to adjust line relief valve (13), loosen locknut (16) and turn adjustment screw (15) until the pressure gauge reading at pressure tap (2) is 36800 ± 1500 kPa (5340 ± 220 psi).

    Note: Turn adjustment screw (15) clockwise in order to increase the pressure. Turn adjustment screw (15) counterclockwise in order to decrease the pressure.

    Note: Always make final pressure adjustment on pressure rise.

15. Tighten locknut (16) on relief valve (13) .

16. Loosen locknut (16) on relief valve (14) on the right stick lowering control valve. Turn adjustment screw (15) counterclockwise by one quarter turn to the marked position. Tighten locknut (16) .

Adjustment (Stick Cylinder Rod End)

1. 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 the full STICK IN position (full retraction of stick cylinder). Hold the joystick for the stick in this position.

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

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

4. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (2) is not within the specification, adjust line relief valve (6) that is on the main control valve.

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Illustration 7	g00949462
Line relief valve (typical example) (11) Adjustment screw (12) Locknut

5. In order to adjust line relief valve (6), loosen locknut (12) and turn adjustment screw (11) until the pressure gauge reading at pressure tap (2) is 36800 ± 1500 kPa (5340 ± 220 psi).

   Note: Turn adjustment screw (11) clockwise in order to increase the pressure. Turn adjustment screw (11) counterclockwise in order to decrease the pressure.

   Note: Always make final pressure adjustment on pressure rise.

6. Tighten locknut (12) on the stick line relief valve.

Adjustment (Work tool Cylinder)

1. To adjust the line relief valve pressure setting of the cylinder head end, move the joystick for the work tool until the work tool is at the full WORK TOOL CLOSE position (full extension of work tool cylinder). Hold the joystick for the work tool in this position.

2. Check the pressure in the cylinder head end on the pressure gauge at pressure tap (1) .

3. Return the joystick for the work tool to the NEUTRAL position.

4. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (1) is not within the specification, adjust line relief valve (5) that is on the main control valve.

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Illustration 8	g00949462
Line relief valve (typical example) (11) Adjustment screw (12) Locknut

5. In order to adjust the relief valve, loosen locknut (12) on the line relief valve. Turn adjustment screw (11) until the pressure gauge reading at pressure tap (1) is 36800 ± 1500 kPa (5340 ± 220 psi).

6. Tighten locknut (12) on the line relief valve.

7. To adjust the line relief valve pressure setting of the cylinder rod end, move the joystick for the work tool until the work tool is at the full WORK TOOL OPEN position (full retraction of work tool cylinder). Hold the joystick for the work tool in this position.

8. Check the pressure in the cylinder rod end on the pressure gauge at pressure tap (1) .

9. Return the joystick for the work tool to the NEUTRAL position.

10. The pressure gauge reading should be 36800 ± 1500 kPa (5340 ± 220 psi). If the pressure gauge reading at pressure tap (1) is not within the specification, adjust the line relief valve that is on the bottom of the main control valve.

11. Loosen locknut (12) on the line relief valve. Turn adjustment screw (11) until the pressure gauge reading at pressure tap (1) is 36800 ± 1500 kPa (5340 ± 220 psi).

    Note: Turn adjustment screw (15) clockwise in order to increase the pressure. Turn adjustment screw (15) counterclockwise in order to decrease the pressure.

    Note: Always make final pressure adjustment on pressure rise.

12. After completion of line relief valve adjustment, tighten locknut (12) .