- The steering pump controls are suspect.
- Blockages, restrictions, or kinks in hoses, lines, or tubes
- Oil leaks in hoses, lines, or tubes or at fittings
- The hydraulic oil is too thick or the type of oil is incorrect.
- Charge pump becomes too inefficient and cannot produce the required pressures
- The NEUTRAL setting for the steering pump is improperly adjusted.
Note: Care must be taken in order to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. You must be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component that contains fluid. Dispose of all fluids according to local regulations.
The Steering Pump Controls Are Suspect
Ensure that the control solenoids for the steering pump are operating properly. Refer to Diagnostic Code Procedures in this manual for troubleshooting a diagnostic code that may be logged.
Blockages, Restrictions, Or Kinks In Hoses, Lines Or Tubes
Blockages, kinks, or restrictions in both the supply and return oil lines can prevent oil flow to or from the steering motor and can create unusual noises due to the high pressures involved. The steering motor cannot turn without oil flow to the pump and from the pump. Check for these conditions on all hydraulic oil hoses, lines, and tubes in the steering system.
Oil Leaks In Hoses, Lines Or Tubes Or At Fittings
Check for leaks at all fittings and connections of hydraulic oil hoses, lines, and tubes in the system in question. Correct any problems that are found then retest for the symptoms.
Leaks at fittings and connections on the pressure side of pumps are a direct source of oil loss in the system. Component failure can result if the low oil levels are not monitored and pumps and motors are starved of oil.
Leaks at fittings and connections on the suction side of pumps are a direct source of oil aeration, cavitation, component damage, and can also create excess or unusual noise.
Leaks at fittings and other types of hydraulic line connections can cause loss of oil flow and prevent components from attaining pressures necessary to perform work. Pressure loss generates complaints of weak force such as the blade tilt or the lift force and implements drifting while in the HOLD condition. Flow losses generate complaints of component speed such as the fan speed or the cylinder speed.
The Hydraulic Oil Is Too Thick Or The Type Of Oil Is Incorrect.
Ensure that oil is the correct viscosity for the operating conditions. In order to determine the correct oil viscosity, refer to the Operation and Maintenance Manual, SEBU9127, "Lubricant Viscosities and Refill Capacities".
Charge Pump Becomes Too Inefficient And Cannot Produce The Required Pressures
Refer to Specifications, Systems Operations, and Testing and Adjusting, UENR4065, "Piston Pump (Steering Charge and Pilot Pressure) - Test and Adjust". If the charge pump becomes too inefficient and cannot produce the required oil flow and pressures, steering will be slow to react, turns will not be as sharp, or the machine may not steer at all.
The Neutral Setting For The Steering Pump Is Improperly Adjusted
Test the mechanical neutral position for the steering pump control valve. Refer to Specifications, Systems Operations, and Testing and Adjusting, UENR4065, "Piston Pump (Steering Charge and Pilot Pressure) - Test and Adjust".
If the neutral position of the steering pump control valve is incorrect (off-center while in the NO STEER condition), the steering pump control valve will command the actuator piston to move off-center when there is no steering request. This condition may cause the machine to drive from straight-line travel in a NO STEER condition, and may cause the machine to steer more sharply in one direction than the other.