Introduction
Two relief valves are located in the head of the swing motor. These relief valves limit the pressure in the left and right swing circuits to the swing relief valve settings. The following procedure will determine if the swing relief valves are out of adjustment.
| NOTICE |
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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. |
Required Tools
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| Illustration 1 | 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 34,450 kPa (5,000 psi) |
1 | |
| B3 | 198-4236 | Extension Cable | 1 | |
| 6V-9828 | Cap | 1 | ||
| 6V-9507 | Plug | 1 | ||
| 4J-5477 | O-Ring Seal | 1 | ||
Machine Preparation
- 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".
- Attach a 34,450 kPa (5,000 psi) pressure sensor to pressure tap (1) .
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| Illustration 2 | g02198096 |
Main control valve (1) Pressure tap | |
- Disconnect line (3) from adapter (2) on the main control valve to engage the swing parking brake. Install 6V-9828 Cap on adapter (2). Install 6V-9507 Plug and 4J-5477 Seal on line (3) .
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| Illustration 3 | g02198754 |
Bottom right corner of main control valve (2) Adapter assembly (3) Pilot line for swing brake engagement | |
Test Procedure
- Start the engine.
- Increase the hydraulic oil temperature to 50° ± 10°C (122° ± 18°F).
- Place the engine speed dial to the HIGH IDLE position. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.
- Place the hydraulic activation control lever in the UNLOCKED position.
- Move the swing joystick slowly and ensure that the swing parking brake is operating properly.
- Slowly move the swing joystick for a full SWING RIGHT operation and check the pressure for relief valve (5) at pressure tap (1). Refer to Table 2 for swing relief pressure.
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| Illustration 4 | g02198753 |
Swing motor (top view) (4) Relief valve (left swing) (5) Relief valve (right swing) | |
- Return the joystick to the NEUTRAL position.
- Slowly move the swing joystick for a full SWING LEFT operation and check the pressure for relief valve (4) at pressure tap (1). Refer to Table 2 for swing relief pressure.
- Return the joystick to the NEUTRAL position.
Adjustment Procedure
- In order to adjust the swing relief valve, loosen the locknut and turn the adjustment plug until the pressure reading at pressure tap (1) is within the specification.
Note: Turning the adjustment plug clockwise increases the pressure. Turning the adjustment plug counterclockwise decreases the pressure.
Note: Always make final pressure adjustments on pressure rise.
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| Illustration 5 | g02198755 |
Line relief valve on the swing motor (A) Adjustment screw (L) Locknut | |
- Tighten the locknut to a torque of 117 ± 10 N·m (85 ± 7 lb ft).
Worksheet
| "Relief Valve (Swing) - Test and Adjust" | |||
| Date | Machine Serial Number | ||
| Machine Settings | Engine Speed | HIGH IDLE | |
| Item | Specification | Actual | |
| 304C CR | 305C CR | ||
| Right Swing | 21900 - 24900 kPa (3176 - 3611 psi) |
21200 - 24200 kPa (3075 - 3510 psi) |
|
| Left Swing | |||