CP56, CS56, CP64, CS64, CP74 and CS74 Vibratory Soil Compactors Machine Systems Steering System Troubleshooting Caterpillar


Steering System Troubleshooting
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1.1. Operational Checks
2.1. Probable Causes of Problems in the Steering System

------ WARNING! ------

Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your AVSpare dealer for replacement manuals. Proper care is your responsibility.


------ WARNING! ------

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing 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.


------ WARNING! ------

Personal injury can result from rotating and moving parts. Stay clear of all rotating and moving parts.

Never attempt adjustments while the machine is moving or the engine is running unless otherwise specified.

The machine must be parked on a level surface and the engine stopped.

Attach a "Do Not Operate" or similar warning tag to the start switch and controls before servicing, repairing, or making adjustments to the machine.


------ WARNING! ------

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or near the machine.

To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.


------ WARNING! ------

Personal injury can result from hydraulic oil pressure and hot oil.

Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.



NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. 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 in AVSpare machines.

Dispose of all fluids according to local regulations and mandates.


Operational Checks

Note: The checks during operation can be used to find leakage in the system. These checks can also be used to find a bad valve, a bad pump, or a bad motor.

Probable Causes of Problems in the Steering System

Problem

The gear pump is noisy and the steering cylinder rods do not move easily.

Probable Cause

  • Air in the steering hydraulic circuit

  • The gear pump is worn.

  • There is a loose connection in the oil line that is connected to the inlet side of the steering pump.

  • The hydraulic oil level is low.

  • Viscosity of the hydraulic oil is not correct.

Problem

Too much force is needed to turn the steering wheel.

Probable Cause

  • The relief valve is stuck open.

  • The hydraulic oil level is low.

  • The oil pressure in the gear pump is too low.

  • The compactor is operating on concrete or asphalt.

  • The metering pump is faulty.

  • The hydraulic oil is cold.

  • Alignment of steering column is not correct.

Problem

The machine does not turn when the steering wheel is turned.

Probable Cause

  • The hydraulic oil level is low.

  • There is air in the hydraulic system.

  • There is dirt in the hydraulic system.

  • The gear pump is faulty.

  • The frame articulation is locked because the lock pin is in the hole in the yoke.

  • One of the steering cylinders has worn piston rings.

Problem

The machine turns slowly in both directions.

Probable Cause

  • There is not enough oil flow from the gear pump.

  • The suction line in the gear pump is restricted.

  • Metering pump operation is not correct.

  • Seal leakage in the steering cylinders.

  • The priority valve spool that is inside the gear pump does not allow enough oil to go to the metering pump.

  • The pressure in the steering circuit is too low.

Problem

Machine turns slowly in one direction.

Probable Cause

  • There is a restriction in the metering pump.

Problem

The metering pump does not return to the center position correctly. Probable Cause

  • The metering pump is faulty.

  • Alignment of the steering column is not correct.

  • The valve spool in the metering pump has a restriction.

  • One of the steering cylinders is not functioning properly.

Problem

Temperature of hydraulic oil is too hot.

Probable Cause

  • Viscosity of the hydraulic oil is not correct.

  • Air is mixed with the hydraulic oil.

  • The relief valve in the steering system has a defect.

  • There is a restriction in one of the steering system lines or components.

  • The oil cooler fins are dirty.

  • The steering pump is faulty.

  • The cooling fan is not at the proper rpm.

  • The thermal bypass valve is faulty.

Problem

When the steering system pressure is tested, the system does not reach the relief valve pressure setting of 19000 ± 300 kPa (2750 ± 45 psi).

Probable Cause

  • The relief valve is not properly adjusted.

  • The relief valve is faulty.

  • The pump is faulty.

Problem

The steering wheel turns without manually turning the wheel.

Probable Cause

  • The metering pump is faulty.

  • The temperature of the oil is too hot.