CP34 and CS34 Vibratory Soil Compactors Machine Systems Caterpillar

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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.

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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, 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.

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 rod does not move easily.

Probable Cause

• Air in the steering hydraulic circuit

• The gear pump is worn.

• Malfunction in the priority valve

• The steering relief valve is malfunctioning.

• Malfunction in the steering control unit

• 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 open.

• The hydraulic oil level is low.

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

• The steering metering unit is faulty.

• The steering relief valve is malfunctioning.

• Malfunction of the priority valve

• 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.

• The steering relief valve is malfunctioning.

• The priority valve is malfunctioning.

• There is dirt in the hydraulic system.

• The operation of the gear pump is not correct.

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

• The steering cylinder has worn piston rings allowing oil to bypass internally.

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 cylinder.

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

• Leakage has caused low pressure in the steering circuit.

• The steering metering unit relief pressure is set too low.

Problem

Machine turns slowly in one direction.

Probable Cause

• There is a restriction in the metering pump.

• Low steering metering unit relief pressure setting.

Problem

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

Probable Cause

• Malfunction of the metering pump

• Alignment of the steering column is not correct.

• The steering cylinder is not functioning properly.

• Contamination

Problem

Temperature of hydraulic oil is too hot.

Probable Cause

• Hydraulic oil cooler bypass valve malfunction.

• 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.

• There is reduced air flow through the hydraulic oil cooler.

Problem

The steering wheel turns without manually turning the wheel.

Probable Cause

• Malfunction of steering control unit