The steering system transmits steering wheel movement to the tires to turn your vehicle in the direction you want it to go. The suspension system helps stabilize the up-and-down and side-to-side motions of your vehicle as you travel over hills, rough roads and make turns. When one or both systems wear, your comfort and safety are compromised by:
  • Rough ride

  • Unnecessary and costly tire wear

  • Excessive vehicle roll or tipping while cornering

  • Noises

  • Difficult steering

  • Loss of vehicle control
Problems with these systems often come on gradually. Have a certified technician check over your steering and suspension every 3,000 miles so problems don't leave you stranded.

Steering System
A well-maintained steering system ensures smooth and problem-free turning. Neglected, it is unsafe and can result in the breakdown of your vehicle.

Rack-and-Pinion Steering
Many of today's vehicles, especially front wheel drive, make use of a rack-and-pinion steering system. When the driver turns the steering wheel, the system converts the steering force into vehicle direction change. In the power-assisted rack-and-pinion steering gear, hydraulic fluid pressure from the power steering pump is used to reduce steering effort. Manual rack-and-pinion systems operate in a similar fashion but with out power assist. Failure of the rack-and-pinion can require greater steering force to change steering direction. Symptoms/problems include:
  • Turning imbalance—harder to turn one direction over the other.

  • Hard to turn when first driven in the morning

  • Front-end wander—will not track in a straight line with movement left and right

  • Poor steering wheel returnability—where the steering wheel does return to center unaided by the driver after making a turn

  • Rattle or knocking noises from steering gear

Here are the main components of a non-rack-and-pinion steering system, what they do, and what trouble signs to look for:
  1. Steering Linkage: Consists of the steering column shaft, steering gearbox, inner and outer tie rods, idler and pitman arms (on some vehicles) and related bushings and bearings.
    Trouble Signs: Difficulty turning or the need to constantly correct steering to keep the vehicle straight, popping noises, squeaks, a binding sensation when turning the steering wheel.

  2. Steering Box: Contains the gears that convert steering wheel rotation to left and right; most cars use rack and pinion steering, many trucks use conventional pitman and idler arm steering.
    Trouble Signs: Steering wheel off-center, loose or hard steering, metal-to-metal or popping sounds, fluid leaks.

  3. Tie Rod: Consists of inner and outer (end) rods that when moved left or right by gearbox action pivot steering knuckles at front wheels and turn the vehicle.
    Trouble Signs: Wheel shimmy, loose steering, tire wear, loss of steering control.

  4. Steering Knuckle: Links front wheel to tie rods and the steering gearbox; may support front brakes, hubs, bearings, wheels and tires; technically part of the suspension system.
    Trouble Signs: Hard turning, looseness.

  5. Ball Joints: Ball-in-socket type components that attach steering knuckles to upper and lower control arms. Considered the pivot points of the steering system.
    Trouble Signs: Wheel shimmy, hard steering, tire misalignment and tire wear; clunking noises upon turning.

Suspension System
Suspension systems, like steering, consist of many interrelated components. These include:
  1. Shock Absorbers: Gas or oil-filled tubular units that dampen coil spring oscillation, absorbing road shocks.
    Trouble Signs: Leaks, loss of oscillation control, springy, difficult-to-control ride.

  2. Coil Springs: Support vehicle weight to allow up and down motion of suspension system; control body sway and lean; used in conjunction with shock absorbers on many vehicles.
    Trouble Signs: Loss of vehicle height, side droop while vehicle is standing or in forward motion, rough or springy ride.

  3. Torsion Bars: Lengths of spring steel rod used instead of springs that twist to absorb vehicle's up-and-down motion.
    Trouble Signs: Loss of vehicle height, which will affect wheel alignment.

  4. MacPherson Struts: A combination of strut and shock absorber mounted inside a coil spring that is used on most front wheel driver cars; also used on some rear wheel suspension units.
    Trouble Signs: Clunking, binding, loss of spring oscillation control, springy and difficult-to-control ride.

  5. Stabilizer Bar: Links suspension system of two opposing wheels—controls body sway.
    Trouble Signs: Vehicle diving or tipping into turns, binding, clunking.

  6. Control Struts: Keeps rear axle assembly aligned; motorists forget that rear end alignment is as critical to vehicle stability and long tire life as is front-end alignment.
    Trouble Signs: Rear tire wear, droopy rear end. Crab-like vehicle travel down the road.