Specification
| "Pressure Reducing Valve (Signal Limiter) - Test and Adjust" | ||||
|---|---|---|---|---|
| Date | Machine Serial Number | |||
| Machine Settings | Engine Speed | |||
| High Idle (1500 rpm) | ||||
| Item | Pressure Reducing Valve | Relief Pressure Setting | Actual | |
| 1a | Boom Cylinder | Extend | Maximum (1) | |
| 1b | Boom Cylinder | Retract | 6,895 to 10,342 kPa (1,000 to 1,500 psi) |
|
| 2a | Stick Cylinder | Extend | Maximum (1) | |
| 2b | Stick Cylinder | Retract | Maximum (1) | |
| 3a | Grapple Cylinder (Close) (2) | Extend | 22,753 to 24,132 kPa (3,300 to 3,500 psi) |
|
| 3b | Grapple Cylinder (Open) (2) | Retract | 13,790 ± 15,168 kPa (2,000 ± 2,200 psi) |
|
| 4a | Boom Cylinder | Extend | Maximum (1) | |
| 4b | Boom Cylinder | Retract | 6,895 to 10,342 kPa (1,000 to 1,500 psi) |
|
| 5 | Grapple (Rotate) (2) | CCW | 15,169 kPa (2,200 psi) |
|
| 6 | Cab Lift Cylinder (Up/(Down) | Extend/Retract | 23,442. kPa (3,400 psi) |
|
| 7 | Cab Lift Cylinder (For/Aft) | Extend/Retract | 23,442. kPa (3,400 psi) |
|
| 8a | Stick Cylinder | Extend | Maximum (1) | |
| 8b | Stick Cylinder | Retract | Maximum (1) | |
| 9a | Steering Cylinder | Left | 21,029 kPa (3,050 psi) |
|
| 9b | Steering Cylinder | Right | 21,029 kPa (3,050 psi) |
|
| ( 1 ) | The signal limiter pressure reducing valve is set to the same pressure as the line relief valve. |
| ( 2 ) | The pressure setting can very depending on the model of grapple that is being used. |
Introduction
The pressure setting for the manifold is controlled by a pressure reducing valve and the pressure relief valves. Relief valves are set to release hydraulic fluid back to the tank when the relief setting has been reached.
Note: Prior to performing this test, the Testing and Adjusting, "Hydraulic System Pressure - Test and Adjust (Anti-Cavitation)" must be performed.
Required Tools
 | |
| Illustration 1 | g02571852 |
Tooling (A) 198-4240 Digital Pressure Indicator Gp | |
| Required Tools | ||||
|---|---|---|---|---|
| Tool | Item | Qty | Part Number | Description |
| A | 198-4240 | Digital Pressure Indicator Gp | ||
| A1 | 1 | 198-4234 | Digital Indicator | |
| A2 | 1 | 198-4239 | Pressure Sensor Gp ( 0 to 41,368 kPa (0 to 6,000 psi)) |
|
| A3 | 1 | 198-4236 | Adapter Cable As | |
Machine Preparation
- Clear all personnel from the machine and from the area around the machine.
- Start the engine.
| NOTICE |
|---|
To avoid system damage, make sure that the hydraulic pump is properly filled with hydraulic oil before start-up. |
- Place the hydraulic activation control lever in the UNLOCKED position.
- Press button "A" on the monitor to set the engine speed at "Max Speed".
 | |
| Illustration 2 | g03095556 |
Engine speed control "Max Speed" as displayed on the programmable function key on the monitor. | |
- Push down on the parking brake control button in order to de-activate the parking brake.
Note: The green indicator light will be illuminated when the parking brake is de-activated.
 | |
| Illustration 3 | g03094559 |
Parking brake control button located on the soft panel switch | |
- Push down on the swing brake control button in order to de-activate the swing brake.
Note: The green indicator light will be illuminated when the swing brake is de-activated.
 | |
| Illustration 4 | g03094697 |
Swing brake control button located on the soft panel switch | |
- Increase the hydraulic oil temperature to 46 to 80° C (115 to 176° F).
- Position the machine on level ground. Check the visibility and adjust the mirrors for the best vision close to the machine.
- Push down on the stabilizer control button in order to lower the stabilizer to the ground.
 | |
| Illustration 5 | g03094816 |
Stabilizer lower control button located on the soft panel switch | |
- Lower the work tool to the ground.
- Place the hydraulic activation control lever in the LOCKED position.
- Stop the engine.
- Connect tooling (A2) 0 to 41,368 kPa (0 to 6,000 psi) pressure sensor to the load sensing signal pressure tap.
 |
Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
 |
| NOTICE |
|---|
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. 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 in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. |
 | |
| Illustration 6 | g03166705 |
Load sensing signal pressure tap is located behind the right side access door. | |
Test Procedure
- Start the engine.
| NOTICE |
|---|
To avoid system damage, make sure that the hydraulic pump is properly filled with hydraulic oil before start-up. |
- Place the hydraulic activation control lever in the UNLOCKED position.
- Press button "A" on the monitor to set the engine speed at "Max Speed".
- Slowly operate the circuit that is being tested to the full EXTEND position or full RETRACT position and hold.
 | |
| Illustration 7 | g03224298 |
View of upper main control valve (1a) Boom (retract) (1b) Boom (extend) (2a) Grapple open (retract) (2b) Grapple close (extend) (3a) Stick (retract) (3b) Stick (extend) (4a) Boom (retract) (4b) Boom (extend) (5) Grapple rotate (CCW) (6) Cab lift (for/aft) (7) Cab lift (up/down) (8a) Stick (retract) (8b) Stick (extend) | |
 | |
| Illustration 8 | g03224296 |
View of lower main control valve (9a) Steering (right) (9b) Steering (left) | |
- Check the pressure for the circuit that is being tested at the load sensing signal pressure tap.
Note: Refer to Table 1 in this procedure for the correct pressure.
- If the signal pressure is not correct, refer to the "Adjustment Procedure".
Adjustment Procedure
- Adjust the pressure for signal limiter pressure reducing valve that is being tested by slowly operating the circuit to the full EXTEND position or full RETRACT position and hold.
- Loosen the locknut on signal limiter pressure reducing valve.
|
Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
|
- Turn the adjustment screw until the pressure reading at the load sense pressure tap for the circuit that is being adjusted has reached the correct pressure.
Note: Refer to Table 1 in this procedure for the correct pressure.
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 the final pressure adjustments on the pressure rise.
- While the adjustment screw on the load sensing signal limiter valve is being held, tighten the locknut.
- Verify that the pressure is within specification.