312F and 313F Excavator Machine Systems Relief Valve (Crossover) - Test and Adjust Caterpillar

Specification

Illustration 1	g02792639

Introduction

The crossover relief valves are located on the travel counterbalance valves. The following procedure will determine if the crossover relief valves are out of adjustment.

Required Tools

Illustration 2	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

Illustration 3	g03261789
(D) Track Block

Machine Preparation

1. Position the machine on level ground.

2. Stop the engine.

3. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".
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   Illustration 4	g02790579
   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 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1). Use this pressure sensor to monitor the crossover relief valve pressure setting of the right travel motor.

5. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (2). Use this pressure sensor to monitor the crossover relief valve pressure setting of the left travel motor.

Test Procedure

Note: A temporary setting of the right forward travel crossover relief is required before the temporary setting of the main relief.

Note: A temporary setting of the main relief valve is required before any crossover relief valves can be adjusted. Refer to Table 4 for temporary main relief setting for the function being tested.

Note: A continuous relief of the valve for more than 10 seconds is not allowed.

Note: Pressure values in Table 5 are approximate values. Use a pressure gauge for adjustment.

Illustration 5	g02791539
Travel brake valve (left side) (5) Locknut (6) Adjustment screw (7) Crossover relief valve (forward left travel) (8) Crossover relief valve (reverse left travel) (9) Locknut (10) Adjustment screw

1. Mark the original position of the right forward travel crossover relief valve.

2. Loosen the locknut for the right forward travel crossover relief valve. Turn the adjustment screw clockwise by one half turn. Tighten the locknut.
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   Illustration 6	g03328754
   (D) Track block (3) Sprocket

3. Place track block (D) in sprocket (3) to block forward right travel.

4. Start the engine.

5. Place the hydraulic activation control lever in the UNLOCKED position.

6. 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.

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

8. Slowly move the right travel control lever to full FORWARD position.

9. Check the main relief valve pressure setting at pressure tap (1). The main relief valve pressure setting should be 35000 ± 500 kPa (5076 ± 73 psi).
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   Illustration 7	g02561037
   Main relief valve (standard) (A) Adjustment screw (L) Locknut

10. Loosen the locknut. Set the temporary main relief pressure to 37500 ± 500 kPa (5439 ± 73 psi). Tighten the locknut.

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

    Note: Always make final pressure adjustments on pressure rise.

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    Illustration 8	g03261818
    Sprocket (left travel) (D) Track block (4) Sprocket

11. Place track block (D) in sprocket (4) to block forward left travel.

12. Slowly move the left travel control lever to full FORWARD position.

13. Check the pressure setting of the left forward travel crossover relief.

14. Loosen the locknut of the left forward travel crossover relief valve. Turn adjustment screw of the left forward travel crossover relief valve until the pressure reading at pressure tap (2) is 35000 kPa (5076 psi).

15. Slowly move the left travel control lever to full FORWARD position.

16. Check the pressure setting of the left forward travel crossover relief.

17. Loosen the locknut of the left forward travel crossover relief valve. Turn adjustment screw of the left forward travel crossover relief valve until the pressure reading at pressure tap (2) is 37500 ± 500 kPa (5439 ± 73 psi).

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

    Note: To prevent over setting, the adjustment should be stopped immediately after the pressure becomes within specification.

18. Remove track block (D) from sprocket (4).

19. Place track block (D) in sprocket to block reverse left travel.

20. Slowly move the left travel control lever to full REVERSE position.

21. Check the pressure setting of the left reverse travel crossover relief.

22. Loosen the locknut of the left reverse travel crossover relief valve. Turn adjustment screw of the left reverse travel crossover relief valve until the pressure reading at pressure tap (2) is 35000 kPa (5076 psi).

23. Slowly move the left travel control lever to full REVERSE position.

24. Check the pressure setting of the left reverse travel crossover relief.

25. Loosen the locknut of the left reverse travel crossover relief valve. Turn adjustment screw of the left reverse travel crossover relief valve until the pressure reading at pressure tap (2) is 37500 ± 500 kPa (5439 ± 73 psi).

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

    Note: To prevent over setting, the adjustment should be stopped immediately after the pressure becomes within specification.

26. To adjust the crossover relief valves on the right travel motor, place the track block (D) in the sprocket for right travel. Use the pressure tap (1) to monitor the crossover relief valve pressure settings for the right travel motor.

27. Return the main relief valve pressure to the specified setting after crossover relief valve pressure setting is attained. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".

Adjustment Procedure

Illustration 9	g03328200
Crossover relief valve (A) Adjustment screw (L) Locknut

1. Loosen locknut and turn adjustment screw to increase or decrease pressure.

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

   Note: Always make final pressure adjustments on the pressure rise.

2. Tighten the locknut to specification once all adjustments are complete.