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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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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 | ||
| Part Number | Description | Qty |
| 1U-5481 | Pressure Gauge Group | 1 |
| 1U-5482 | Pressure Adapter Group | 1 |
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| Illustration 1 | g00282546 |
(1) Pressure tap. (2) Pilot selector and pressure control valve. | |
Note: Prior to testing the pilot system pressure, make sure that the standby pressure of the steering pump is within the specification. The maximum standby pressure of the steering pump is 4700 kPa (680 psi). For more information about the low pressure standby test procedure, refer to the Service Manual module Testing and Adjusting, "Steering Pump Low Pressure Standby - Test" for the machine that is being serviced.
- Attach a hose assembly to pressure tap (1). Attach the hose assembly to the 8T-0850 Pressure Gauge (0 to 4,000 kPa (0 to 580 psi)).
- Start the engine and run the engine at high idle. Raise and lower the lift arms repeatedly in order to warm the hydraulic oil to normal operating temperature. The hydraulic oil must be at a temperature of 55° to 80°C (130° to 180°F) in order to obtain accurate results.
- With the engine at high idle, check the oil pressure reading on the pressure gauge. The oil pressure must be 3000 ± 400 kPa (435 ± 60 psi).
- Stop the engine. If the oil pressure is within specifications, disconnect the test equipment from pressure tap (1). If the oil pressure is not within specifications, proceed to Step 5.
- Release the pressure in the hydraulic system. For more information about releasing hydraulic system pressure, refer to the Service Manual module Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.
- Remove plug (3). Add spacers (5) between the plug and spring (4) in order to increase the pressure. Remove spacers (5) in order to decrease the pressure. Use the following spacers in order to change the pressure:
- The 5S-7001 Spacer (Thick) with a thickness of 0.90 mm (.035 inch)
- The 5S-7018 Spacer (Thin) with a thickness of 0.25 mm (.010 inch)
The addition or removal of a 5S-7001 Spacer (Thick) will change the hydraulic pressure by 290 kPa (42 psi).
The addition or removal of a 5S-7018 Spacer (Thin) will change the hydraulic pressure by 80 kPa (12 psi).
Note: The 5S-7001 Spacer (thick) must contact the spring. The 5S-7018 Spacer (thin) must contact the plug.
- The 5S-7001 Spacer (Thick) with a thickness of 0.90 mm (.035 inch)
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| Illustration 2 | g00282547 |
Pilot Selector and Pressure Control Valve (3) Plug. (4) Spring. (5) Spacers. | |
- Install plug (3). Repeat Steps 2 and 3.