The suspension system in your car does several things, all related to rider comfort and safety. It cushions you and your vehicle's components from the road's bumps and pits, it stabilizes the vehicle during turns, and protects the vehicle and you from excess vibration and the noise it can cause.
Your vehicle's suspension system is made up of several parts:
Each of these has a role to play in the vehicle's suspension.
How Do I Tell If Something's Wrong With The Suspension?
There are several signs of a worn or broken suspension system. Each sign will give you a good idea of what is actually wrong and should be fixed or replaced.
Springy or Mushy-feeling Ride
If your car has a lot of "spring" and bounce when going over bumps or turning corners and if it "clunks" when going over speed bumps or on the transition from driveway to roadway, then it's likely that your shock absorbers are broken. You'll need to replace them quickly or begin having problems with your springs as well. Read about shock absorber replacement.
On a small car, you may have shocks built into your springs (these are called "spindles" or "struts"). In this case, the whole unit must be replaced as one. Read about strut replacement
Lots of Road Noise, Squeaking
This is a sign that your body mount bushings are worn out. These provide a cushion between the vehicle's frame and the body and when they wear out, they allow metal-to-metal contact between the two, causing noise and vibration. This translates to more road noise and squeaking sounds. These bushings should be replaced as they are also weak points for rust and corrosion. Read more about bushings
Vehicle Rides Low, "Clunks" Instead of Bouncing
This is a good indication that one or more of your leaf or coil springs has broken. Most vehicles use coil springs, though some larger trucks and SUVs may have leaf springs on the rear axle. In either case, if the springs are broken or have come loose, the vehicle will have no suspension at all and will quickly destroy its own shock absorbers and may begin suffering braking problems as well. In many vehicles, the tire will begin rubbing inside the wheel well too. Springs should be replaced before operating the vehicle further.
Leaking or Cracked Shock Absorber
Most shock absorbers are filled with fluid to help absorb and store energy for a rebound when hitting bumps. When the absorber becomes old or is damaged, it will crack and leak this fluid out. The shock should be replaced as soon as possible when this happens. Read about shock absorber replacement
Difference between shocks and struts
When to change shocks
How to replace shocks
About car bushings
How do I know if I need new shocks?
Leaf spring suspension
Progressive Suspension Shocks