Testing and Adjusting the Load Sensing Valve
Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility. |
Introduction
Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
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 testing and the adjusting procedures provide a means of checking and a means of adjusting the pressure setting of the internal load sensing valve.
The load sensing valve is designed to match the outlet flow of the piston pump with the demand by the system.
Required Tools
Hydraulic test procedures may be performed using either one of the following test equipment:
- Caterpillar DataView
- Standard tooling
Caterpillar DataView
Illustration 1 | g00920192 |
Caterpillar DataView |
Table 1 provides a list of the required tools if Caterpillar Dataview is used to perform the following test procedure. Caterpillar DataView is not shown in the following test procedure.
Required Tools (Caterpillar DataView)     | ||
---|---|---|
Part Number     | Description     | Qty     |
131-5051     | DataView Tool Gp     | 1     |
4C-6819     | Pressure Sensor     | 1     |
131-5063     | Adapter Cable As     | 1     |
Reference: Refer to Tool Operating Manual, NEHS0662, "Caterpillar DataView" for additional information about using Caterpillar DataView.
Standard Tooling
Illustration 2 | g00934260 |
Use the tools in Table 2 to complete the following test procedure.
Required Tools     | ||||
---|---|---|---|---|
Tooling     | Part Number     | Description     | Qty     | |
A     | A1     | 8T-0858     | Pressure Gauge     | 2     |
6V-3989 | Fitting | 2     | ||
A2 | 6V-4143     | Coupler     | 4     | |
177-7860 | Hose As     | 2     |
Test Procedure
Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
Perform the following procedure before you perform the test procedure that follows:
- Park the machine on a level area that is clear from all equipment and material.
- Verify that the service brake system and the parking brake system are in good working order.
- Block the drive wheels in both directions.
- Apply the parking brake.
- Start the engine and warm the oil to a minimum temperature of 60 °C (140 °F).
- Stop the engine.
Hot oil and components can cause personal injury. Do not allow hot oil or components to contact skin. |
High hydraulic system pressure. To avoid personal injury, do not remove any hydraulic system lines, taps, or parts until all pressure has been relieved. |
- Locate control valve (1) for the generator.
Illustration 3 | g00933917 |
- Locate port "TP1" (2) and port "TP2" (3) on the control valve.
Illustration 4 | g00945112 |
- Assemble Tooling (A1) and Tooling (A2) in order to make Tooling (A) .
- Install Tooling (A) on port "TP1" (2) and port "TP2" (3) .
Note: When the load sensing valve is adjusted correctly, there will be a pressure difference of 1400 kPa (203 psi) between port "TP1" and port "TP2".
- Start the engine. Place throttle control switch (4) in high idle position (5) .
Illustration 5 | g00933988 |
- Place toggle switch (6) for the generator in ON position (7) .
Illustration 6 | g00933989 |
- Record the pressure reading at port "TP1". Record the pressure reading at port "TP2". Subtract the pressure reading at port "TP2" from the pressure reading at port "TP1". The difference between the two pressures should be 1400 kPa (203 psi).
- If the difference between the two pressures is not 1400 kPa (203 psi), perform the procedure in "Adjustment Procedure for the Load Sensing Valve".
- If the difference between the two pressures is 1400 kPa (203 psi), go to the Step 10.
- Stop the engine.
- Remove Tooling (A) on both port "TP1" (2) and port "TP2" (3) .
Adjustment Procedure for the Load Sensing Valve
Note: Tooling (A) should still be installed on the control valve and the engine should still be running.
- Locate adjustment screw (8) and locknut (9) on the generator pump.
Illustration 7 | g00934126 |
Bottom View of the Piston Pump |
- Loosen locknut (9). Turn adjustment screw (8) in the clockwise direction in order to increase the pressure reading at port "TP2". Turn the adjustment screw in the counterclockwise direction in order to decrease the pressure reading at port "TP2".
- Stop the engine.
- Remove Tooling (A) on both port "TP1" (2) and port "TP2" (3) .
Testing and Adjusting the Pressure Compensator Valve
Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility. |
Introduction
Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
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 testing and adjusting procedures provides a means of checking and adjusting the pressure setting for the pressure compensator valve. The pressure compensator valve in this system is designed to be used as a high pressure relief valve.
Required Tools
Hydraulic test procedures may be performed using either one of the following test equipment:
- Caterpillar DataView
- Standard tooling
Caterpillar DataView
Illustration 8 | g00920192 |
Caterpillar DataView |
Table 3
Required Tools (Caterpillar DataView)     | ||
---|---|---|
Part Number     | Description     | Qty     |
131-5051     | DataView Tool Gp     | 1     |
4C-6819     | Pressure Sensor     | 1     |
131-5063     | Adapter Cable As     | 1     |
Reference: Refer to Tool Operating Manual, NEHS0662, "Caterpillar DataView" for additional information about using Caterpillar DataView.
Standard Tooling
Illustration 9 | g00934320 |
Tooling (B) |
Use the tools in Table 4 to complete the following test procedure.
Required Tools     | ||||
---|---|---|---|---|
Tooling     | Part Number     | Description     | Qty     | |
B     | B1     | 177-7860     | Hose As     | 1     |
6V-4143 | Coupler | 2     | ||
B2 | 8T-0859     | Pressure Gauge     | 1     | |
6V-3989 | Fitting     | 1     | ||
C     | -     | 6V-9509     | Face Seal Plug     | 1     |
D     | -     | 110-6349     | Fitting As     | 1     |
Test Procedure
Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
Perform the following procedure before you perform the test procedure that follows:
- Park the machine on a level area that is clear from all equipment and material.
- Verify that the service brake system and the parking brake system are in good working order.
- Block the drive wheels in both directions.
- Verify that the service brake system and the parking brake system are in good working order.
- Block the drive wheels in both directions.
- Apply the parking brake.
- Start the engine and warm the oil to a minimum temperature of 60 °C (140 °F).
- Stop the engine.
Hot oil and components can cause personal injury. Do not allow hot oil or components to contact skin. |
High hydraulic system pressure. To avoid personal injury, do not remove any hydraulic system lines, taps, or parts until all pressure has been relieved. |
- Locate hydraulic gear motor (10) on the generator.
Illustration 10 | g00934107 |
- Disconnect hose (11) from the gear motor. Hose (11) is the pressure hose.
- Install Tooling (C) in the end of hose (11) .
Note: Plugging the end of hose (11) will prevent pressure oil to flow through the gear motor. As a result, the oil pressure will increase in the circuit until the pressure compensator valve opens at the adjusted setting.
- Locate piston pump (12) .
Illustration 11 | g00934110 |
- Remove the plug at port "M2" (13) .
- Install Tooling (D) at port "M2".
- Install Tooling (B) on Tooling (D) .
- Start the engine. Place throttle control switch (4) in high idle position (5) .
Illustration 12 | g00933988 |
- Check the pressure at port "M2". The pressure reading will be the pressure setting of the pressure compensator valve. If the pressure reading at port "M2" is 14995 kPa (2175 psi), the test is completed. Go to Step1. If the pressure reading is incorrect, go to the Step 10.
- Stop the engine.
- Remove Tooling (C) from the end of hose (11). Install hose (11) to the gear motor.
- Remove Tooling (B) from Tooling (D) .
- Remove Tooling (D) from port "M2" (13) on the generator pump.
- Install the plug at port "M2" (13) .
- Make sure that the lines are secure and check for leaks.
Adjustment Procedure
- Locate adjustment screw (15) and locknut (16) for the pressure compensator valve at the front of piston pump.
Illustration 13 | g00933993 |
- Loosen locknut (16) .
- Observe the pressure reading at Tooling (B). The pressure should be 14995 kPa (2175 psi). If the pressure reading is less than 14995 kPa (2175 psi), turn adjustment screw (15) in the clockwise direction until you obtain the correct pressure reading. If the pressure reading is more than 14995 kPa (2175 psi), turn adjustment screw (15) counterclockwise until you obtain the correct pressure reading.
- Tighten locknut (16) after you have obtained the correct pressure reading. The test is complete.
- Stop the engine.
- Perform Step 11 through Step 15 in "Test Procedure" in order to remove the tooling.