 |
|
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, 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. |
|
|
Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks. |
| 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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
| "Relief Valve (Line) - Test and Adjust" | |||
|---|---|---|---|
| Date | Machine Serial Number | ||
| Machine Settings | Main Relief Pressure(1) | Engine Speed | |
| |
HIGH IDLE | ||
| Cylinder | Cylinder Position | Relief Pressure Setting | Actual |
| Boom | Extended | |
|
| Retracted | |||
| Stick | Extended | |
|
| Retracted | |||
| Bucket | Extended | |
|
| Retracted | |||
| Blade
(if equipped with angle blade) |
Extended | |
|
| Angle Blade
(if equipped) |
Extended | |
|
| Retracted | |
||
| Thumb
(if equipped) |
Extended | |
|
| Retracted | |||
| (1) | System pressure setting before temporary setting adjustment |
The line relief valves are located between each cylinder and the respective control valve. The line relief valve limits the overload pressures that can be created in the implement cylinders. The line relief valves are located on the top and bottom of the main control valve.
| |
| Illustration 1 | g02068598 |
|
Line relief valve (L) Locknut (A) Adjustment screw | |
| |
| Illustration 2 | g01623868 |
|
Tooling group "B" 198-4240 Digital Pressure Indicator Gp | |
| Tool | Item | Part Number | Description | Qty |
|---|---|---|---|---|
| B | 198-4240 | Digital Pressure Indicator Gp | ||
| B1 | 198-4234 | Indicator | 1 | |
| B2 | 198-4238 | Pressure Sensor
|
1 | |
| B3 | 198-4236 | Extension Cable | 3 | |
- Position the machine on level ground and stop the engine.
- Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
Show/hide table
Illustration 3 g02198096 Main control valve
(1) Pressure tap - Attach the
34,450 kPa (5,000 psi) pressure sensor to pressure tap (1). - Start the engine.
- Increase the engine speed lever to the HIGH IDLE position. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)".
- Increase the hydraulic oil temperature to
50° ± 10°C (122° ± 50°F) .
Temporary Setting of the Main Relief Valve
- A temporary setting of the main relief valve is required before any line relief valves can be adjusted.
- Move the joystick for the bucket until the bucket is at the full BUCKET CLOSE position (full extension of bucket cylinder).
- Check the main relief valve pressure setting at pressure tap (1).
- Be sure that the main relief valve pressure is set at the pressure specification. Refer to Table 1.
Note: Always make final pressure adjustments on pressure rise.
Show/hide table
Illustration 4 g02198098 Main control valve
(2) Main relief valve - Loosen the locknut. Turn the adjustment screw clockwise for one half turn. Tighten the locknut.
- Reset main relief valve pressure setting to the normal operating condition after the completion of the line relief test and adjust. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".
- Start the engine.
- Increase the engine speed lever to the HIGH IDLE position. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)".
- Increase the hydraulic oil temperature to
55° ± 5°C (131° ± 9°F) . - Operate the implement joystick in the appropriate direction in order to relieve the valve.
Note: A continuous relief of the valve for more than 10 seconds is not allowed.
- Check the relief valve pressure setting at pressure tap (1). Refer to Table 1 for the pressure specifications of the line relief valves.
- Return the joystick to the NEUTRAL position.
Adjustment (Cylinder Head End)
| |
| Illustration 5 | g02198434 |
|
Line relief for the boom lowering control valve located on the boom cylinder | |
- 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 reading at pressure tap (1).
- Return the joystick for the boom to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve that is on the drift reduction valve.
- To adjust the line relief valve, loosen the locknut. Then turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 6 | g02198435 |
|
Line relief for the boom cylinder head end | |
- 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 reading at pressure tap (1).
- Return the joystick for the boom to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve that is on the drift reduction valve.
- To adjust the line relief valve, loosen the locknut. Then turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 7 | g02198674 |
|
Line relief valve for the boom cylinder rod end | |
- Move the joystick for the boom to the full BOOM LOWER position. Hold the joystick for the boom in this position and check the pressure reading at pressure tap (1).
- Check the pressure reading for the boom cylinder rod end at pressure tap (1).
- Return the joystick to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the boom cylinder rod ends.
- Loosen the locknut on the line relief valve for the boom cylinder rod end. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
Note: If an appropriate location is not available for full extension of the boom cylinders, exchange the functions of the boom line relief valve. Remove the line relief valves for the boom cylinder head end and 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 (Cylinder Head End)
| |
| Illustration 8 | g02198675 |
|
Line relief valve for the stick cylinder head end | |
- To adjust the line relief valve pressure setting of the stick cylinder head end, move the joystick for the stick until the stick is at the full STICK IN position (full extension of stick cylinder). Hold the joystick for the stick in this position.
- Check the pressure reading for the stick cylinder head end at pressure tap (1).
- Return the joystick for the stick to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the stick cylinder head end.
- To adjust the line relief valve, loosen the locknut. Then turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 9 | g02198713 |
|
Line relief valve for the stick cylinder rod end | |
- 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 OUT position (full retraction of stick cylinder). Hold the joystick for the stick in this position.
- Check the pressure reading in the stick cylinder rod end at pressure tap (1).
- Return the joystick for the stick to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve that is on the drift reduction valve.
- In order to adjust the line relief valve, loosen the locknut. Then turn the adjustment screw until the pressure reading at pressure tap (2) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
Adjustment (Cylinder Head End)
| |
| Illustration 10 | g02198714 |
|
Line relief valve for the bucket cylinder head end | |
- To adjust the line relief valve pressure setting of the bucket cylinder head end, move the joystick for the bucket until the bucket is at the full BUCKET CLOSE position (full extension of bucket cylinder). Hold the joystick for the bucket in this position.
- Check the pressure reading in the bucket cylinder head end at pressure tap (1).
- Return the joystick for the bucket to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the bucket cylinder head end.
- In order to adjust the line relief valve, loosen the locknut on the bucket line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 11 | g02198715 |
|
Line relief valve for the bucket cylinder rod end | |
- To adjust the line relief valve pressure setting of the bucket cylinder rod end, move the joystick for the bucket until the bucket is at the full BUCKET OPEN position (full retraction of bucket cylinder). Hold the joystick for the bucket in this position.
- Check the pressure reading in the bucket cylinder rod end at pressure tap (1).
- Return the joystick for the bucket to the NEUTRAL position.
- The pressure reading should be to the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve.
- In order to adjust the line relief valve, loosen the locknut on the bucket line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
Adjustment (Cylinder Head End)
| |
| Illustration 12 | g06027877 |
|
Line relief valve for the angle blade cylinder head end | |
- To adjust the line relief valve pressure setting of the angle blade cylinder head end, press the control for the angle blade until the blade angle is at the full left angle position (full extension of angle blade cylinder). Hold the control for the angle blade in this position.
- Check the pressure reading in the angle blade cylinder head end at pressure tap (1).
- Return the control for the angle blade to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the angle blade cylinder head end.
- In order to adjust the line relief valve, loosen the locknut on the angle blade line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 13 | g06027879 |
|
Line relief valve for the angle blade cylinder rod end | |
- To adjust the line relief valve pressure setting of the angle blade cylinder rod end, press the control for the angle blade until the blade angle is at the full right angle position (full retraction of blade angle cylinder). Hold the control for the angle blade in this position.
- Check the pressure reading in the angle blade cylinder rod end at pressure tap (1).
- Return the joystick for the angle blade to the NEUTRAL position.
- The pressure reading should be to the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve.
- In order to adjust the line relief valve, loosen the locknut on the angle blade line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
Blade (If Equipped with Angle Blade)
Adjustment (Cylinder Head End)
| |
| Illustration 14 | g06029280 |
|
Line relief valve for the blade cylinder head end | |
- To adjust the line relief valve pressure setting of the blade cylinder head end, press the control for the blade until the blade is at the full blade LOWER position (full extension of blade cylinder). Hold the control for the blade in this position.
- Check the pressure reading in the blade cylinder head end at pressure tap (1).
- Return the control for the blade to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the blade cylinder head end.
- In order to adjust the line relief valve, loosen the locknut on the blade line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
| |
| Illustration 15 | g03734263 |
|
(3) Line relief for the thumb cylinder head end
(4) Line relief for the thumb cylinder rod end | |
Adjustment (Cylinder Head End)
- To adjust the line relief valve pressure setting of the thumb cylinder head end, move the control for the thumb until the thumb is at THUMB CLOSE (full extension of thumb cylinder). Hold the control for the thumb in this position.
- Check the pressure reading in the thumb cylinder head end at pressure tap (1).
- Return the control for the thumb to the NEUTRAL position.
- The pressure reading should be within the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief valve for the thumb cylinder head end (3).
- In order to adjust the line relief valve, loosen the locknut on the thumb line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.
- To adjust the line relief valve pressure setting of the thumb cylinder rod end, move the control for the thumb until the thumb is at the full THUMB OPEN (full retraction of thumb cylinder). Hold the control for the thumb in this position.
- Check the pressure reading in the thumb cylinder rod end at pressure tap (1).
- Return the control for the thumb to the NEUTRAL position.
- The pressure reading should be to the specification. Refer to Table 1. If the pressure reading at pressure tap (1) is not within the specification, adjust the line relief for the thumb cylinder rod end (2).
- In order to adjust the line relief valve, loosen the locknut on the thumb line relief valve. Turn the adjustment screw until the pressure reading at pressure tap (1) is within the specification. Refer to Table 1.
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 final pressure adjustment on pressure rise.
- Tighten the locknut on the line relief valve.