1212 Golf Road

Waukegan, Illinois

(847) 623-9609

Steering and suspension are kindred spirits.  Steering is about controlling the right, left and straight directional movements of your car. Suspension is about controlling its up-and-down movement as it travels over the uneven road surface. These two systems not only share some of the same components, they each contribute to the other's performance. They also affect your safety since they heavily influence a car's "handling." The more responsive your vehicle is, the safer it is.  Repairs done to the suspension and steering systems are collectively known sometimes as "front-end" work, but some suspension components are located in the rear as well.

The two most common types of steering systems are the conventional (or parallelogram) steering system, and the rack and pinion steering system. 

In the conventional steering system, the steering wheel is attached to a steering shaft that sits inside the steering column.  As the steering wheel is turned, the rotational movement is transferred down the shaft to a steering gearbox.  The steering box has an arm attached to the output shaft called the pitman arm.  The pitman arm is connected to one end of the center link.  In the other end of the center link is an idler arm. Between the idler and pitman arms, the center link is supported in the proper position to keep the left and right wheels working together. 

The inner tie rod ends are attached to either end of the center link and provide pivot points for the steering gear. From there, it goes to the outer tie rod ends through an adjustment sleeve.  This sleeve joins the inner and outer tie rod ends together and allows for adjustment when the front wheels are aligned.  The outer tie rod ends are connected to the steering knuckle  that actually turns the front wheels.  The steering knuckle has an upper and lower ball joint that it pivots on.                  

Rack-and-pinion steering is somewhat different.  Rack & pinion steering eliminates the traditional steering gearbox and in essence combines it and the center link into one unit by replacing it with a simpler set of gears. A toothed piston called a pinion gear is attached to the end of the steering shaft where it meets a long bar or rack, that also has teeth.  One end of the inner tie rod is connected to either end of the rack and the other end is connected directly to the outer tie rod end which attaches the rack to the wheels. Rack & pinion steering is the popular and light-weight steering mechanism found in most modern cars and light trucks.  The advantage is that it is more precise than the mechanical system.  By reducing the number of parts and pivot points, it can more accurately control wheel direction and is more responsive.  The down side is that they are prone to leakage requiring replacement of the rack assembly as a unit.

Power steering utilized fluid under pressure to provide most of the turning force to the front wheels.  This assistance comes from a belt-driven power steering pump .  The hydraulic pump pressurizes the fluid and sends it through a pressure hose to the steering gear or rack. The fluid pressure increases turning power.  Consequently, less manual pressure is needed to turn the steering wheel. 
 

Suspension components support the body & chassis and attaches them to the wheels.  The suspension system interacts directly with the steering system to provide vehicle control.  The variety of suspension system designs is great, but all have a common purpose of absorbing shocks, which provides a comfortable ride, while keeping the wheels in constant contact with the road surface.

Suspension components typically include springs, shocks, struts, bushings, ball joints, control arms, strut rods, and the sway bar.

Front Suspension

There are two major types of front suspension systems.  In the conventional system, springs are used to absorb the energy from the wheels and support most of the car weight.  They compress to absorb impact and extend to release itl.  Either coil springs (most common, look like oversized metal Slinkies) or torsion bars (a long spring steel rod which takes the place of a conventional spring and absorbs motion by twisting) are typically mounted between the frame and the lower control arm (metal arm that attaches to frame by rubber bushings and to the steering knuckle by ball joints).  Ball Joints are the connecting ball-and-socket joints of the steering and suspension systems.  They allow the steering components to move up and down as well as side-to-side.  Shock absorbers are hydraulic units that dampen the vibrations of the springs. 

Some vehicles are equipped with round steel strut rods that are attached between the lower control arm at one end and the frame of the vehicle with rubber bushings to provide forward/backward support to the control arms. 

Most front wheel drive vehicles use the MacPherson strut system which combines the coil spring and the shock absorber into one component.  The internal shock absorber dampens movement of the spring as it compresses and rebounds during vehicle travel. The strut housing serves as a structural part of the suspension system and connects the upper strut bearing to the lower ball joint so that the entire assembly can pivot when the steering wheel is turned.

Rear Suspension

Most vehicles generally use either coil, leaf spring or MacPherson strut suspension systems.  Leaf springs absorb the motion of the wheels as the uneven strips of metal of which they're made flatten and unflatten.  These are used on many 4 wheel drive vehicles. 

Automatic Level Control

This system is used to provide proper vehicle ride height while carrying heavy loads.  Air shock/strut units are combined with a built-in air compressor and ride height sensor(s) to provide automatic ride height control. 

Computerized Ride Control

This electronic system uses a series of sensors that feed information about vehicle speed, braking and other handling characteristics to a control module.  The control module then adjusts the ride (by altering spring and shock absorber movements) for changing road conditions.