Suspension, struts, springs, shocks
The suspension of an automobile includes the struts, springs, shock absorbers and linkages that connect a vehicle's frame to the tires. Some feel it is one of the most important parts of a vehicle. It gives your passengers a comfortable ride, reduces vibrations that could damage your car and it keeps your tires on the road during rapid maneuvers. Vehicles built for off road have a "beefed up" suspension to handle the extra abuses of off-roading.
Suspension systems are designed to be extremely hard wearing, but normal wear and use will wear out parts that could eventually break. To avoid an expensive breakdown you should have a trained technician inspect the system during regular maintenance. This is especially true if you notice excessive bouncing, bottoming out, if your vehicle leans far to the side when turning corners or makes noises when bumps are hit.
Dependent and Semi-Dependent Suspension
There are many different types of suspension available, but for the most part, they can be categorized as dependent and independent. Dependent suspensions have a rigid axle that connects the wheels. Movement on one side affects the wheel on the other side. Semi dependent suspension works the same way, but the tires are not attached by a ridged axle. Dependent and semi-dependent suspension are commonly found on big vehicles that carry heavy loads. The axle is kept in place by leaf springs and shock absorbers.
Independent Suspension
Independent suspension is a broad term used to describe a suspension system that allows each wheel to move independently of each other. This is what is used in most vehicles because it offers a better ride quality and handling characteristics. Springs and shocks are used to absorb the bumps in the road and sway bars usually connect the left and right sides of the suspension. There is an array of independent suspension types from the Mcpherson, double wishbone, trailing arm, twin beam . . . some having more than one version.
Sway Bar
A sway bar or stabilizer bar, connects the left and right wheels together through a short lever arm. It increases the suspension's roll sjpgfness and reduces an automobile's "body lean" while cornering. Cars used in auto racing usually have a sway bar that can be adjusted for different cornering situations. The sway bar is not commonly replaced unless it is worn down or breaks under abusive conditions.
Control Arm
The control arm is an important part of your vehicle's suspension that works with the strut to control the motion of the wheels in relation to your vehicle. It is located at the top and bottom of the wheel spindle at the end of the drive shaft. The control arm works in unison with your car’s wheels and can be recognized by its "A" or "Y" shape. Too much movement and your car will wander all over the road wearing down parts in the rest of the suspension system. Problems with control arms are usually caused by worn bushings.
Springs
There are three types of springs: coil, torsion bars, and leaf springs. Coil springs are the most widely used on today's vehicles. The weight of the vehicle rests on the spring and absorbs the bumps in the road.
Torsion bars look similar to coil springs except their performance is based on the twisting properties of the bar.
Leaf springs were used on older vehicles up to about the middle of the 1980's and are used in most heavy duty vehicles. They are easily recognized by layers of metal connected to the axle.
A low sitting chassis or sloppy handling is usually the first sign that the springs are wearing out.
Shock Absorbers (Dampers)
Without shock absorbers, your car would be very bouncy. They absorb the shock of large bumps and keep your suspension at full travel to give your tires traction. Some shock absorbers may be adjustable to sjpgfen or loosen the suspension. There are a wide variety of types of shock absorbers, including:
- adjustable shock absorbers
- air shock absorbers
- direct-acting shock absorbers
- double-tube shock absorbers
- friction shock absorbers
- gas shock absorbers
- lever-type shock absorbers
- single-tube shock absorbers
- telescopic shock absorbers
Coil Over Oil Unit
The coil over oil unit is a spring and shock absorber all-in-one. Instead of having a valve, an adjustable "spring plate" is used to adjust the dampening of this unit. These units can be quite sophisticated, having adjustable compression damping as well as a remote reservoir.
Shocks will wear out over time which is most noticeable when your vehicle seems to bounce more, your tires start wearing unevenly, degraded road handling, or oil leakage from the shocks.
Strut
A strut bar, strut brace, or strut tower is usually an aftermarket car suspension accessory. These are similar to shock absorbers as they both reduce the shock from bumps in the road. Struts are arms that move up and down, carrying and dispersing the weight of the car as it hits bumps. The struts have several parts that work together to achieve a smooth ride. They include the shock absorbers or springs and control arms.
There are a few different problems that could occur with struts, which would keep your vehicle from operating at its best. The rear and front strut mounts have different problems depending on the make, model and year of your vehicle. Struts should be replaced in sets, either the front or back. All bearings and bushings should also be replaced and a four wheel alignment is recommended because all the new parts will affect the old alignment.
These are just a few of the many different types and combinations of suspensions, and it is difficult to list them all. Narrowing down a problem to one part can also be difficult if you are unfamiliar with the system. You will usually feel vibrations in the steering, clunking, or excessive bouncing when bumps are hit and excessive or unusual wearing of your tires. The most common problems are the shock absorbers or the springs, but if your vehicle is going to be in the shop to repair one, you should probably get both replaced. It could save you money and time in the long run.
