Testing and Adjusting the Flushing Valve
Introduction
This test is designed to determine if the flushing valve for each propel motor 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, "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. |
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 | g00935733 |
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 | 198-4237 | Pressure Sensor 0 - 3450 kPa (0 - 500 psi) |
1 | |
Standard Tooling
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| Illustration 2 | g00935734 |
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| Illustration 3 | g00935735 |
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 | 1 |
| 6V-4143 | Coupler | 2 | ||
| B2 | 8T-0855 | Pressure Gauge 0 - 4000 kPa (0 - 580 psi) |
1 | |
| 6V-3989 | Fitting | 1 | ||
| C | - | 4C-6500 | Digital Thermometer | 1 |
Test Procedure
The 198-4240 Digital Pressure Indicator was used in the following test.
Before you conduct the test procedure on the flushing 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: This testing procedure measures the pressure for the flushing valve of the drum propel motor. Follow the same test procedure and the same adjustment procedure for the flushing valve on the axle propel motor.
- Remove brake line (1). Plug the brake line and cap the fittings.
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| Illustration 4 | g00935737 |
(1) Brake line | |
- Connect Tool (A2) to pressure test port (2) .
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| Illustration 5 | g00935736 |
Test ports for the flushing valves (2) Test port for the charge relief valve of the drum propel pump | |
- 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).
- Move the propel control lever in the FORWARD position. Record the pressure at test port (2). The pressure should read220 ± 150 kPa (32 ± 22 psi) less than system charge pressure.
- If the pressure reading is acceptable, move the propel control lever in the REVERSE position. Record the pressure at test port (2). The pressure should read 220 ± 150 kPa (32 ± 22 psi) less than the system charge pressure.
Adjusting Procedure
- If the pressure for the flushing valve is not correct, replace the relief cartridge (3) in the flushing valve.
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| Illustration 6 | g00935741 |
(3) Flushing relief valve for drum motor | |
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| Illustration 7 | g00935739 |
(4) Flushing relief valve for axle motor | |
- Recheck the pressure at port (2) in both directions.
- Remove pressure sensors and reconnect brake line (1) .