"Suspension," when discussing cars, refers to the use of front and rear springs to suspend a vehicle's "sprung" weight. The springs used on today's cars and trucks are constructed in a variety of types, shapes, sizes, rates, and capacities. Types include leaf springs, coil springs, air springs, and torsion bars. These are used in sets of four for each vehicle, or they may be paired off in various combinations and are attached by several different mounting techniques. The suspension system also includes shocks and/or struts, and sway bars.

Back in the earliest days of automobile development, when most of the car's weight (including the engine) was on the rear axle, steering was a simple matter of turning a tiller that pivoted the entire front axle. When the engine was moved to the front of the car, complex steering systems had to evolve. The modern automobile has come a long way since the days when "being self-propelled" was enough to satisfy the car owner. Improvements in suspension and steering, increased strength and durability of components, and advances in tire design and construction have made large contributions to riding comfort and to safe driving.

Cadillac allegedly produced the first American car to use a steering wheel instead of a tiller.

Two of the most common steering mechanisms are the "rack and pinion" and the standard (or recirculating-ball) systems that can be either manual or assisted by power. The rack and pinion was designed for sports cars and requires too much driver muscle at low speeds to be very useful in larger, heavier cars. However, power steering makes a heavy car respond easily to the steering wheel, whether at highway speeds or inching into a narrow parking place, and it is normal equipment for large automobiles.

The suspension system has two basic functions, to keep the car's wheels in firm contact with the road and to provide a comfortable ride for the passengers. A lot of the system's work is done by the springs. Under normal conditions, the springs support the body of the car evenly by compressing and rebounding with every up-and-down movement. This up-and-down movement, however, causes bouncing and swaying after each bump and is very uncomfortable to the passenger. These undesirable effects are reduced by the shock absorbers.

The above information is directly from the Auto Insight program, which you can buy online from AutoEducation.com.

Common Problems:

• Shocks and struts can wear out and affect handling. If you car bounces excessively over bumps and leans hard in corners, your shocks could be warn. Look behind the wheel for the shock or strut and look for leaking oil. This is a sure sign of a worn shock or strut.

• Ball joints. Ball joints wear and can cause your car to wander while driving down the road. This is dangerous as they can separate and cause you to lose control.

Preventive maintenance:

• Check your shocks or struts for leakage frequently. Also pay attention to how your car handles. If you notice the ride deteriorating take your car in to have the struts checked.

• Ball joints should be checked when your car is inspected, if not, have your mechanic check them at least twice a year.

• At each oil change make sure you or your mechanic lubricates the ball joints and any other suspension components. Some components cannot be lubricated as they are sealed from the factory.