Power Steering: Steering Problems and Causes

POSSIBLE STEERING PROBLEMS AND CAUSES

NORMAL NOISES

  • You or the driver may hear a hissing noise from the control valve when it is actuated during a steering maneuver.
  • You or the driver may hear a noise as fluid bypasses through the poppets at full turn.
  • You or the driver may hear a noise from the system relief valve when it is required to actuate.
  • You or the driver may hear pump growl from some types of power steering pumps

ABNORMAL NOISES

  • If the power steering pump is belt-driven, a squealing noise may indicate that the belts should be tightened or replaced.
  • A clicking noise heard during a turn, or when changing directions, may indicate that some component is loose and shifting under load.
  • A change in the normal noise of the pump may indicate a faulty valve or wear in the pump.
  • A change in the normal noise of the pump may be due to kinked or plugged hoses.
  • Because of the plugged filter, there may be whining from the pump.
  • Improper adjustment of the gearbox will result in abnormal noise from the pump.

ROAD WANDER

  • Tire pressure incorrect or unequal left to right.
  • Components in steering linkage loose or worn (Steering wheel to road wheel).
  • Wheel bearings improperly adjusted or worn.
  • Front end alignment out of specification.
  • Dry fifth wheel or poor finish on the fifth wheel or trailer plate.
  • Steering gear mounting bolts loose on the frame.
  • Steering gear improperly adjusted.
  • Looseness in rear axle assemblies or trailer bogies.

NO RECOVERY

  • Tire pressure low
  • Front end components binding
  • Front end alignment incorrect
  • Tight front axle kingpins
  • Dry fifth wheel or poor finish on the fifth wheel or trailer plate
  • Steering column binding
  • Pump flow insufficient
  • Steering gear improperly adjusted
  • Steering gear control valve sleeve sticking

SHIMMY

  • Badly worn or unevenly worn tires
  • Improperly mounted tire or wheel
  • Wheel bearings improperly adjusted or worn
  • Components in steering linkage loose or worn
  • Wheels or brake drums out of balance
  • Front end alignment incorrect
  • Air in the hydraulic system

EXTERNAL OIL LEAKAGE

  • Finding the location of a leak may be difficult, since oil may run away from leak source, the fittings, hoses, pumps, or gear to a low point on the gear or chassis.
  • A leak from the vent plug at the side cover indicates the failure of the sector shaft oil seal inside the side cover.

OVERSTEERING OR DARTING

  • Dry fifth wheel or poor finish on the fifth wheel or trailer plate
  • Front end components binding or loose
  • Steering column binding
  • Steering gear improperly adjusted
  • Steering gear control valve sleeve sticking
  • Rear-axle mounts (rear steer)

HIGH STEERING EFFORT IN ONE DIRECTION

  • Unequal tire pressure
  • Vehicle overloaded
  • Inadequate hydraulic system pressure
  • Excessive internal leakage in one direction of turn only (verify with internal leakage test)

HIGH STEERING EFFORT IN BOTH DIRECTIONS

  • Low tire pressure
  • Vehicle overloaded
  • Low hydraulic fluid level
  • Low pressure or flow from pump
  • Components of steering system binding
  • Restriction in return line, or line too small in diameter
  • Excessive internal leakage (verify with internal leakage test)
  • Oversize tires (check manufacturer’s specifications)

LOST MOTION (LASH) AT THE STEERING WHEEL

  • Steering wheel loose on the shaft
  • Loose connection between the steering gear, intermediate column, and steering column
  • Steering gear loose on frame
  • Pitman arm loose on the output shaft
  • Components in steering linkage loose or worn
  • Steering gear improperly adjusted
  • Worn front spring bushing

EXCESSIVE HEAT (150º F (65.6º C) OVER AMBIENT). NOT TO EXCEED 250º F (121º C) CONTINUOUSLY

  • Excessive pump flow
  • Vehicle overloaded
  • Undersized replacement hose or line
  • Restricted hose or line that is kinked or severely bent or internally blocked
  • Restricted recentering of gear valve caused by column bind or sideload on the input shaft
  • Poppet not adjusted properly (only for gears equipped with poppets)
  • Prolonged stationary vehicle operation