Group 25, Steering Column and Gear
SM 765, Nov ’06 Steering System Troubleshooting • 25-2-1
No steering
• Hydraulic fluid level very low.
• Air in hydraulic oil.
• Steering column sections not connected properly.
• Hose broken.
• Hydraulic pump contaminated or defective.
• Priority valve spool stuck.
Hard steering
• Hydraulic fluid level low.
• Air in hydraulic oil.
• Steering gear contaminated or defective.
• Relief valve setting too low; adjust or replace.
• System leaking.
• Axle load too heavy.
• Lack of lubrication.
• Defective steering gear.
• Spring in priority valve broken.
High number of handwheel turns
• Steering cylinder seal leakage.
• Worn steering gear.
Steering handwheel spins freely
• Air in system (cavitation).
• Low oil supply.
• Steering column detached from steering gear.
• Defective steering gear.
Jerky steering
• Steering gear malfunction because of worn parts or
contamination. Steering gear may require over-
haul.
Truck turns in wrong direction
• Hydraulic lines not installed correctly.
Handwheel kickback
• Check valve faulty (or not in system).
Slow steering response
• Oil viscosity too high.
• Contaminated or defective steering gear.
Chatter conditions
• Loose mountings or linkage. Make certain all
mounting fasteners and other linkage is tight.
• Pressure relief valve set too low and is out of
adjustment; adjust or replace the relief valve.
• Insufficient pump flow. Check pump for leaks and
see Section 5 of this Group.
Unsatisfactory steering in either direction
• Air in system due to excessive wear in steering cyl-
inder. Check for air in system. Excessive noise or
foamy condition of hydraulic fluid indicates aera-
tion. Check that air is not entering the system
through poor threads, cracked, split, or worn hoses,
bad pump seals, bad O-rings, bad gaskets, or loose
connections.
Worn cylinders result in leakage past the piston.
Overhaul (see Group 26, Section 6) or replace the
steer cylinder.
• Incorrect system pressure due to worn pump.
Replace the relief valve or repair or replace the
hydraulic pump.
Noise during turns
• Worn bearing(s) in steering arm; replace bearings.
• Worn pin in steering knuckle; replace pin.
• Worn bearings in steering knuckle; replace bear-
ings.
• Steering knuckle is loose; tighten castle nut.
Section 2
Steering System Troubleshooting
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