725 and 730 Articulated Trucks Steering, Suspension, and Body Hoist Hydraulic Systems Caterpillar

Signal and Pressure Reducing Valve (Steering) - Check

Usage:

725 AFX

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

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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, "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.

Test the load sensing pressure. Refer to Systems Operation, Testing and Adjusting, "Load Sensing Pressure (Steering) - Test".
If the load sensing pressure is incorrect, there may be a problem with the signal and pressure reducing valve.

Test the response of the machine to a steering input. If the response to a steering input is slow, there may be a problem with the signal and pressure reducing valve. Refer to Systems Operation, Testing and Adjusting, "Operational Checks". If the steering time is incorrect, there may be a problem with the signal and pressure reducing valve.
- One of the components of the signal and pressure reducing valve may be damaged.
- The spool or an orifice may be blocked due to contamination.

Relieve the system pressure. Refer to Systems Operation, Testing and Adjusting, "General Information".

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Illustration 1	g00760520
The signal and pressure reducing valve is located above the left side of the front axle. The signal and pressure reducing valve can also be accessed by raising the cab.

Remove the signal and pressure reducing valve from the machine. Refer to Disassembly and Assembly, RENR3447, "Signal and Pressure Reducing Valve - Remove and Install".

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Remove plug (2) and remove the spool from the signal and pressure reducing valve.

Remove any contamination from the spool and the inside of the signal and pressure reducing valve. Also, remove any contamination from orifice plug (1) .

Check all components for damage. If the seals are damaged, the seals may be replaced. If any other components are damaged, the signal and pressure reducing valve must be replaced.

Reposition the spool inside the signal and pressure reducing valve and tighten plug (2) to a torque of 67.8 ± 13.6 N·m (50 ± 10 lb ft).

Install the signal and pressure reducing valve. Refer to Disassembly and Assembly, RENR3447, "Signal and Pressure Reducing Valve - Remove and Install".