228 and 248 Skid Steer Loaders Machine Systems Caterpillar

Test and Adjust for the 228 Skid Steer Loader Line Relief Valves

Table 1

REQUIRED TOOLS
Part Number	Description	Qty
177-7860	Hoses	2
6V-4143	Coupler Assemblies	4
8T-0860	Gauges 0 to 40,000 kPa	2
6V-3989	Unvalved Nipples	2
6V-9510	Face Seal Plugs	4
6V-9831	Caps	4
7J-9108	O-Ring Seals	4
6V-9511	Face Seal Plugs	4
6V-9832	Caps	4
6V-9746	O-Ring Seals	4
4C-8765	Absorbent Pads	10

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

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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 Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

The following tests are performed in order to determine if the line relief valves are damaged or if the line relief valves are incorrectly set.

Before any tests are performed, visually inspect the complete hydraulic system for oil, leaks, and damaged parts. Refer to the Testing and Adjusting, "Visual Inspection". Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".

1. Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel.

2. Lower the work tool to the ground. Engage the parking brake. Stop the engine.

3. Raise the cab of the machine. For the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Cab Support Operation" for the correct procedure.

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Illustration 1	g00699501

4. Remove the floorplate. The floorplate contains the warning signs.

5. Remove the hose clamp that holds the drain line for the hydraulic tank in position. Move the hose out of your way.

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Illustration 2	g00708764

6. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (5) on tube (1) .

7. Place several 4C-8765 Absorbent Pads under nut (6). Loosen nut (6) on tube (1) .

8. Install one 6V-9831 Cap on the bank valve.

9. Install one 6V-9832 Cap on the tee.

10. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

11. Install the 6V-9510 Face Seal Plug into nut (5) on tube (1) .

12. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

13. Install the 6V-9511 Face Seal Plug into nut (6) on tube (1) .

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Illustration 3	g00708772

14. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (7) on tube (2) .

15. Place several 4C-8765 Absorbent Pads under nut (8). Loosen nut (8) on tube (2) .

16. Install one 6V-9831 Cap on the bank valve.

17. Install one 6V-9832 Cap on the tee.

18. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

19. Install the 6V-9510 Face Seal Plug into nut (7) on tube (2) .

20. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

21. Install the 6V-9511 Face Seal Plug into nut (8) on tube (2) .

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Illustration 4	g00708776

22. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (9) on tube (3) .

23. Place several 4C-8765 Absorbent Pads under nut (10). Loosen nut (10) on tube (3) .

24. Install one 6V-9831 Cap on the bank valve .

25. Install one 6V-9832 Cap on the tee.

26. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

27. Install the 6V-9510 Face Seal Plug into nut (9) on tube (3) .

28. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

29. Install the 6V-9511 Face Seal Plug into nut (10) on tube (3) .

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Illustration 5	g00708779

30. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (11) on tube (4) .

31. Place several 4C-8765 Absorbent Pads under nut (12). Loosen nut (12) on tube (4) .

32. Install one 6V-9831 Cap on the bank valve.

33. Install one 6V-9832 Cap on the tee.

34. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

35. Install the 6V-9510 Face Seal Plug into nut (11) on tube (4) .

36. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

37. Install the 6V-9511 Face Seal Plug into nut (12) on tube (4) .

38. To check the relief valve settings for the lift circuit, the tilt circuit, and the auxiliary hydraulic circuit, increase the setting on the relief valve for the load sense circuit to 30000 kPa (4351 psi).

39. Remove the cap from the relief valve for the load sense circuit.

40. Hold the screw in a stationary position.

41. Mark the screw. Mark the nut. Loosen the nut. To increase the pressure setting, turn the adjustment screw clockwise. Count the number of turns. Tighten the nut.

42. To check the relief valve settings for the high flow auxiliary circuit, increase the pump cutoff setting to 29000 kPa (4206 psi).

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Illustration 6	g00708849

43. Remove cap (13). Mark the nut. Mark the screw.

44. Hold the screw in a stationary position.

45. Loosen the nut. To increase the pressure setting, turn the adjustment screw clockwise.

46. Tighten the nut. Install cap (13) .

47. Install one 6V-4143 Coupler Assembly to each end of the 177-7860 Hose. Install one end of the hose to the test port (14) .

48. Install a 6V-3989 Unvalved Nipple to an 8T-0860 Gauge. Install the 8T-0860 Gauge to the other end of the 177-7860 Hose. Secure the hydraulic line so that the pressure gauge can be viewed by the operator during the test.

49. Lower the cab.

50. Fasten the seat belt. Start the engine. Run the engine at HIGH idle.

51. Raise the work tool off the ground. Move the work tool to the full TILT BACK position. Stall the work tool. Check the pressure.

52. Tilt the work tool forward. Lower the work tool to the ground. Stop the engine. Release the seat belt.

53. Repeat Step 43, Step 44, Step 45, Step 46, Step 47, Step 48, Step 49, Step 50, Step 51, and Step 52 until the pump cutoff setting is 29000 kPa (4206 psi).

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Illustration 7	g00708877

54. Install one 6V-4143 Coupler Assembly to each end of a 177-7860 Hose. Install one end of the hose to the test port (15). Test port (15) is on the bank valve.

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Illustration 8	g00561416

55. Install a 6V-3989 Unvalved Nipple to an 8T-0860 Gauge. Install the 8T-0860 Gauge to the other end of the 177-7860 Hose. Secure the hydraulic line so that the pressure gauge can be viewed by the operator during the test.

56. Lower the cab.

57. Fasten the seat belt. Start the engine.

58. Run the engine at HIGH idle.

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NOTICE
Do not stall the hydraulic system for more than 10 seconds. If necessary, release the work tool from the stall condition and wait 30 seconds before you repeat the following step.

59. Press and hold the left side of the control switch for the auxiliary circuit. Record the pressure at the stall condition.

60. Press and hold the right side of the control switch for the auxiliary circuit. Record the pressure at the stall condition.

61. Move the joystick control and hold the joystick control until a stall condition exists in the following positions: RAISE, TILT FORWARD and TILT BACK. Record the pressures that exist at each of the positions.

62. Press and hold the left side of the control switch for the high flow auxiliary circuit. Record the pressure at the stall condition.

63. Press and hold the right side of the control switch for the high flow auxiliary circuit. Record the pressure at the stall condition.

64. The pressures that are recorded should be equal to the pressures that are listed in the following table:
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    Table 2

    LINE RELIEF VALVE PRESSURES
    	228	Actual
    Head End of the Lift Cylinder RAISE position	28000 ± 700 kPa (4061 ± 102 psi)
    Head End of the Tilt Cylinder TILT FORWARD position	24000 ± 700 kPa (3480 ± 100 psi)
    Rod End of the Tilt Cylinder TILT BACK position	28000 ± 700 kPa (4060 ± 100 psi)
    Auxiliary Circuit	25000 ± 700 kPa (3626 ± 102 psi)
    High Flow Auxiliary Circuit	25000 ± 700 kPa (3626 ± 102 psi)

65. Tilt the work tool until the work tool is parallel with the ground. Lower the work tool to the ground. Stop the engine. If the pressure readings are within specifications, proceed to Step 13 on Page 31. If the pressure readings are not within specifications, proceed to Step 66.

66. Turn the engine start switch key to the ON position.

67. Move the joystick controls to all positions in order to release the pressure in the hydraulic system. Press both sides of the control switch for the auxiliary circuit in order to release the pressure from the auxiliary lines.

68. Turn the engine start switch key to the OFF position.

69. Raise the cab of the machine. For the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Cab Support Operation" for the correct procedure.

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Illustration 9	g00699830

70. Remove the cap (30) from the relief valve (29) that needs to be adjusted.

71. Loosen the locknut (31). The adjustment screw is under the cap. Turn the adjustment screw clockwise in order to increase the relief valve setting. Turn the adjustment screw counterclockwise in order to decrease the relief valve setting.

72. Tighten the locknut (31). Install the cap (30) .

73. Repeat Step 49 and Step 50. To test the relief valve, move the joystick control until a stall condition exists. Adjust the relief valve until the relief valve is within specifications.

74. Install the four tubes on the bank valve. Install tube (4) first. Install the tubes in reverse order.

Set the Cutoff Pressure Setting for the Piston Pump (Work Tool)

After completion of the "Line Relief Valve - Test and Adjust" procedure, perform the following steps on the 228 Skid Steer Loader. The steps set the cutoff pressure setting for the piston pump (work tool).

1. Remove the cap on the relief valve for the load signal. Mark the nut and screw.

2. Set the load signal relief pressure. The specification for the load signal relief pressure is 22000 ± 2000 kPa (3191 ± 290 psi).

3. Set the pump cutoff pressure to 23000 ± 1000 kPa (3336 ± 145 psi).

4. Set the pressure for the relief valve for the load sense circuit to 23600 kPa (3423 psi).

5. Lower the cab. Fasten the seat belt. Start the engine. Run the engine at HIGH idle.

6. To warm the oil, operate the hydraulic circuits .

7. Operate the auxiliary hydraulic circuit to a stall condition.

8. Raise the work tool off the ground. Move the work tool to the full TILT FORWARD position.

9. Move the work tool from the full TILT FORWARD position to the full TILT BACK position. The cycle time from full TILT FORWARD position to the full TILT BACK position should be 5 ± 1 second. Increase the load sensing pressure if the cycle time is slow. To increase the load sensing pressure, turn the load sensing screw clockwise. Decrease the load sensing pressure if the cycle time is too fast. To decrease the load sensing pressure, turn the load sensing screw counterclockwise.

10. Set the relief valve for the load sense circuit. Set the pump cutoff pressure.

11. Install the plate. The plate contains the warning signs.

12. Lower the cab of the machine. For the 228 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7207, "Cab Support Operation" for the correct procedure.

13. If the relief valves are within specifications, proceed to "Hydrostatic System - Test and Adjust" in this module.

Test and Adjust for the 248 Skid Steer Loader Line Relief Valves

Table 3

REQUIRED TOOLS
Part Number	Description	Qty
177-7860	Hoses	2
6V-4143	Coupler Assemblies	4
8T-0860	Gauges 0 to 40,000 kPa	2
6V-3989	Unvalved Nipples	2
6V-9510	Face Seal Plugs	4
6V-9831	Caps	4
7J-9108	O-Ring Seals	4
6V-9511	Face Seal Plugs	4
6V-9832	Caps	4
6V-9746	O-Ring Seals	4
4C-8765	Absorbent Pads	10

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

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, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

The following tests are performed in order to determine if the line relief valves are damaged or if the line relief valves are incorrectly set.

Before any tests are performed, visually inspect the complete hydraulic system for oil, leaks, and damaged parts. Refer to the Testing and Adjusting, "Visual Inspection". Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".

1. Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel.

2. Lower the work tool to the ground. Engage the parking brake. Stop the engine.

3. Raise the cab of the machine. For the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Cab Support Operation" for the correct procedure.

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Illustration 10	g00699501

4. Remove the plate. The plate contains the warning signs.

5. Remove the hose clamp that holds the drain line for the hydraulic tank in position. Move the hose out of your way.

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Illustration 11	g00700424

6. Place several 4C-8765 Pads under the bank valve. Loosen nut (5) on tube (1) .

7. Place several 4C-8765 Pads under nut (6). Loosen nut (6) on tube (1) .

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Illustration 12	g00699197

8. Install one 6V-9831 Cap (7) on the bank valve.

9. Install one 6V-9832 Cap (8) on the tee.

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Illustration 13	g00699211

10. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

11. Install the 6V-9510 Face Seal Plug (9) into nut (5) on tube (1) .

12. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

13. Install the 6V-9511 Face Seal Plug (10) into nut (6) on tube (1) .

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Illustration 14	g00699221

14. Place several 4C-8765 Pads under the bank valve. Loosen nut (11) on tube (2) .

15. Place several 4C-8765 Pads under nut (12). Loosen nut (12) on tube (2) .

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Illustration 15	g00699236

16. Install one 6V-9831 Cap (13) on the bank valve.

17. Install one 6V-9832 Cap (14) on the tee.

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Illustration 16	g00699243

18. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

19. Install the 6V-9510 Face Seal Plug (15) into nut (11) on tube (2) .

20. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

21. Install the 6V-9511 Face Seal Plug (16) into nut (12) on tube (2) .

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Illustration 17	g00699265

22. Place several 4C-8765 Pads under the bank valve. Loosen nut (17) on tube (3) .

23. Place several 4C-8765 Pads under nut (18). Loosen nut (18) on tube (3) .

24. Install one 6V-9831 Cap on the bank valve .

25. Install one 6V-9832 Cap on the tee.

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Illustration 18	g00699275

26. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

27. Install the 6V-9510 Face Seal Plug (19) into nut (17) on tube (3) .

28. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

29. Install the 6V-9511 Face Seal Plug (20) into nut (18) on tube (3) .

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Illustration 19	g00699292

30. Place several 4C-8765 Pads under the bank valve. Loosen nut (21) on tube (4) .

31. Place several 4C-8765 Pads under nut (22). Loosen nut (22) on tube (4) .

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Illustration 20	g00699315

32. Install one 6V-9831 Cap (23) on the bank valve.

33. Install one 6V-9832 Cap (24) on the tee.

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Illustration 21	g00699321

34. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

35. Install the 6V-9510 Face Seal Plug (25) into nut (21) on tube (4) .

36. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

37. Install the 6V-9511 Face Seal Plug (26) into nut (22) on tube (4) .

38. To check the relief valve settings for the lift circuit, the tilt circuit, and the auxiliary hydraulic circuit, increase the setting on the relief valve for the load sense circuit to the maximum setting.

39. Remove the cap from the relief valve for the load sense circuit.

40. Hold the screw in a stationary position.

41. Mark the screw. Mark the nut. Loosen the nut. To increase the pressure setting, turn the adjustment screw clockwise. Count the number of turns. Tighten the nut.

42. To check the relief valve settings for the high flow auxiliary circuit, increase the pump cutoff setting to 33000 kPa (4786 psi).

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Illustration 22	g00699794

43. Remove cap (27). Mark the nut. Mark the screw.

44. Hold the screw in a stationary position.

45. Loosen the nut. To increase the pressure setting, turn the adjustment screw clockwise.

46. Tighten the nut. Install cap (27) .

47. Install one 6V-4143 Coupler Assembly to each end of the 177-7860 Hose. Install one end of the hose to the test port (28) .

48. Install a 6V-3989 Unvalved Nipple to an 8T-0860 Gauge. Install the 8T-0860 Gauge to the other end of the 177-7860 Hose. Secure the hydraulic line so that the pressure gauge can be viewed by the operator during the test.

49. Lower the cab.

50. Fasten the seat belt. Start the engine. Run the engine at HIGH idle.

51. Raise the work tool off the ground. Move the work tool to the full TILT BACK position. Stall the work tool. Check the pressure.

52. Tilt the work tool forward. Lower the work tool to the ground. Stop the engine. Release the seat belt.

53. Repeat Step 43, Step 44, Step 45, Step 46, Step 47, Step 48, Step 49, Step 50, Step 51, and Step 52 until the pump cutoff setting is 33000 kPa (4786 psi).

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Illustration 23	g00699749

54. Install one 6V-4143 Coupler Assembly to each end of a 177-7860 Hose. Install one end of the hose to the test port (29). Test port (29) is on the bank valve.

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Illustration 24	g00561416

55. Install a 6V-3989 Unvalved Nipple to an 8T-0860 Gauge. Install the 8T-0860 Gauge to the other end of the 177-7860 Hose. Secure the hydraulic line so that the pressure gauge can be viewed by the operator during the test.

56. Lower the cab.

57. Fasten the seat belt. Start the engine.

58. Run the engine at HIGH idle.

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NOTICE
Do not stall the hydraulic system for more than 10 seconds. If necessary, release the work tool from the stall condition and wait 30 seconds before you repeat the following step.

59. Press and hold the left side of the control switch for the auxiliary circuit. Record the pressure at the stall condition.

60. Press and hold the right side of the control switch for the auxiliary circuit. Record the pressure at the stall condition.

61. Move the joystick control and hold the joystick control until a stall condition exists in the following positions: RAISE, TILT FORWARD and TILT BACK. Record the pressures that exist at each of the positions.

62. Press and hold the left side of the control switch for the high flow auxiliary circuit. Record the pressure at the stall condition.

63. Press and hold the right side of the control switch for the high flow auxiliary circuit. Record the pressure at the stall condition.

64. The pressures that are recorded should be equal to the pressures that are listed in the following table:
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    Table 4

    LINE RELIEF VALVE PRESSURES
    	248	Actual
    Head End of the Lift Cylinder RAISE position	28000 ± 700 kPa (4061 ± 102 psi)
    Head End of the Tilt Cylinder TILT FORWARD position	24000 ± 700 kPa (3480 ± 100 psi)
    Rod End of the Tilt Cylinder TILT BACK position	28000 ± 700 kPa (4060 ± 100 psi)
    Auxiliary Circuit	25000 ± 700 kPa (3626 ± 102 psi)
    High Flow Auxiliary Circuit	32000 kPa (4641 psi)

65. Tilt the work tool until the work tool is parallel with the ground. Lower the work tool to the ground. Stop the engine. If the pressure readings are within specifications, proceed to Step 79. If the pressure readings are not within specifications, proceed to Step 66.

66. Turn the engine start switch key to the ON position.

67. Move the joystick controls to all positions in order to release the pressure in the hydraulic system. Press both sides of the control switch for the auxiliary circuit in order to release the pressure from the auxiliary lines.

68. Turn the engine start switch key to the OFF position.

69. Raise the cab of the machine. For the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Cab Support Operation" for the correct procedure.

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Illustration 25	g00699830

70. Remove the cap (30) from the relief valve (29) that needs to be adjusted.

71. Loosen the locknut (31). The adjustment screw is under the cap. Turn the adjustment screw clockwise in order to increase the relief valve setting. Turn the adjustment screw counterclockwise in order to decrease the relief valve setting.

72. Tighten the locknut (31). Install the cap (30) .

73. Repeat Step 49 and Step 50. To test the relief valve, move the joystick control until a stall condition exists. Adjust the relief valve until the relief valve is within specifications.

74. Adjust the relief valve for the load sense circuit. On the 248 Skid Steer Loader, the pressure is 27000 ± 2000 kPa (3916 ± 290 psi).

75. Adjust the cutoff pressure for the piston pump (work tool). On the 248 Skid Steer Loader, the pressure is 29000 ± 1000 kPa (4206 ± 145 psi).

76. Install the four tubes on the bank valve. Install tube (4) first. Install the tubes in reverse order.

77. Install the plate. The plate contains the warning signs.

78. Lower the cab of the machine. For the 248 Skid Steer Loader, refer to the Operation and Maintenance Manual, SEBU7255, "Cab Support Operation".

79. If the relief valves are within specifications, proceed to "Hydrostatic System - Test and Adjust" in this module.