Testing and Adjusting the Pressure Override Relief Valve
Introduction
This test is designed to determine if the pressure override relief valve is functioning properly.
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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. |
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| 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, "AVSpare Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on AVSpare products. Dispose of all fluids according to local regulations and mandates. |
Required Tools
Hydraulic test procedures may be performed using either one of the following test equipment:
- Digital Pressure Indicator
- Standard tooling
Digital Pressure Indicator
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| Illustration 1 | g00929387 |
Table 1 provides a list of the required tools if the 198-4240 Digital Pressure Indicator is used to perform the following test procedure.
| Required Tools Digital Pressure Indicator |
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|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| A | A1 | 198-4234 | Digital Pressure Indicator | 1 |
| A2 | 198-4239 | Pressure Sensor 0 - 69000 kPa (0 - 10000 psi) |
2 | |
Standard Tooling
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| Illustration 2 | g00929389 |
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| Illustration 3 | g00929402 |
Table 2 provides a list of the required tools if standard tooling is used to perform the following test procedure.
| Required Tools (Standard Tooling) | ||||
|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| B | B1 | 177-7860 | Hose As | 2 |
| 6V-4143 | Coupler | 4 | ||
| B2 | 8T-0861 | Pressure Gauge 0 - 60000 kPa (0 - 8700 psi) |
2 | |
| 6V-3989 | Fitting | 2 | ||
| C | - | 4C-6500 | Digital Thermometer | 1 |
| D | D1 | 6V-9830 | Cap | 1 |
| D2 | 6V-9509 | Plug | 1 | |
| E | E1 | 177-7860 | Hose As | 1 |
| E2 | 6V-4143 | Coupler | 2 | |
Test Procedure
The 198-4240 Digital Pressure Indicator was used in the following test.
Before you conduct the test procedure on the pressure override relief valve (POR valve), the following steps must be performed:
- Make sure that the parking is applied.
- Place the propel control lever in NEUTRAL position.
- Place the machine in position against a solid, stationary object such as a loading dock. The wheels and the drum may be blocked instead of placing the machine against a stationary object.
Note: Follow the same test procedure and the same adjustment procedure for the POR valves on the axle propel pump and the drum propel pump.
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| Illustration 4 | g00929404 |
Final drive planetary (1) Brake line | |
- Remove brake line (1). Plug the brake line and cap the fittings with Tool (D).
- Connect Tool (E) between the X1 and X2 ports that are located on the axle propel pump.
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| Illustration 5 | g00946032 |
Axle propel pump | |
- Connect two Tools (A2) to pressure test ports (2) .
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| Illustration 6 | g00929405 |
Test for the Pressure Override Relief Valve (POR Valve) on the Drum Propel Pump (2) Pressure test ports (3) Balance lines | |
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| Illustration 7 | g00935732 |
(4) POR valve | |
- Release the parking brake. Move the parking brake switch to the OFF position. This position will allow the pumps to upstroke.
- Start the machine and run the engine at high idle at 2310 ± 50 rpm. Check the hydraulic temperature with Tool (C) until the hydraulic oil temperature reaches 38°C (100°F).
- Set the speed range switch to the HIGH SPEED position.
- Move the propel control lever in the FORWARD position. Record the pressure at test port (2). The pressure should be 44000 ± 1000 kPa (6380 ± 145 psi).
- Repeat step 7 for the REVERSE position.
Adjusting Procedure
- If the pressure at the POR valve is not correct, adjust POR valve (4). Use a 13 mm wrench in order to loosen the locknut. Use a 4 mm Allen wrench in order to adjust the relief pressure of the POR valve. Turn the adjusting screw clockwise in order to increase the pressure. Turn the adjusting screw counterclockwise in order to decrease the pressure.
- Recheck the pressure at port (2) in both directions.
- Remove plugs and reconnect brake line (1) .
- Remove Tool (E) .