What Is A Shock Absorber And Why Is It Important?

Your GM vehicle has a shock absorber behind either 2 wheels or all 4 wheels. A shock absorber is a hydraulic tube that attaches to the vehicle in two places:

  1. The top end of the shock absorber attaches to the frame or body.
  2. The bottom end of the shock absorber attaches to the lower control arm, or axle.


GM shock absorber #15780243, for select 2008-2011 Chevrolet HHR's.

Shock absorbers absorb most of the vibrations and bumps on the road. They exist to:

  • Keep your car’s ride quality as smooth and comfortable as possible
  • Keep your vehicle's tires in contact with the road at all times
  • Limit the vehicle's body movements (such as swaying or nosediving)
  • Keep your vehicle's steering, road handling, and braking response optimal

In this guide, you’ll learn about shock absorbers and why they’re important.

How Does A Hydraulic Shock Absorber Work?

A shock absorber may look and function like a simple part, but it's quite useful when your vehicle is on the road. Shock absorbers are some of the most fundamental elements of the suspension system. A hydraulic shock absorber's design enables it to:

  1. Convert the kinetic energy from the suspension movement into heat energy
  2. Dissipate the heat energy through hydraulic fluid

The shock absorbs most of the kinetic energy from the road. So it helps keep your car's steering, road handling, brake response, and ride quality as optimal as possible.

Looking for a simpler description? We got you covered. Here's how a shock absorber works, in layman's terms:

The Components Of A Shock Absorber

A shock absorber has a bunch of components, which include:

  • Tube
  • Piston
  • Piston rod
  • Hydraulic oil
  • Pressure tube
  • Base valve
  • Reserve cylinder

The Inner Workings Of A Shock Absorber

Inside the shock absorber, the piston has a bunch of tiny holes in it. There's also hydraulic fluid inside the tube, beneath the piston.

So when you drive over a bump on the road, the shock compresses. When that happens, the hydraulic fluid squeezes through the tiny holes in the piston. This creates a damping effect that absorbs most of the impact from the road. This size of the holes determines how firm or soft the shock feels. If you need some visual aid, here's a gif from this video:

After the bump, the shock absorber extends back to normal length. When this happens, the piston compresses the fluid in the chamber above it. So the shock absorbers on your car constantly compress and decompress. The bumpier the road, the harder the shock absorbers work.

Each OEM shock absorber is designed for a certain vehicle. For example, GM optimized OEM shock absorbers to handle the weight of the vehicle's body and the weight of the wheels and tires.

Why A Bad Shock Absorber Is Bad News

Under normal circumstances, a shock absorber lasts about 50,000 miles. It may fail sooner or later though. As a car owner, you want to keep an eye out for signs of failed shocks so you can replace them as soon as possible.

A bad shock absorber on your GM vehicle brings several undesirable consequences, such as:

  • Rough and uncomfortable ride quality
  • Decreased handling
  • Faster wear of the tires and suspension components
  • More dive when braking, which means longer stops

Replacing Your Shock Absorbers

Changs shock

You should always replace your shock absorbers in pairs (on the same axle). It’s to help keep both sides balanced.

Replacing your shock absorbers is a pretty straightforward process. So you can easily do it at home. All you have to do is to:

  1. Lift your vehicle
  2. Remove the wheels
  3. Remove the top and bottom bolts
  4. Remove the old shock absorber
  5. Install the new shock absorber in the reverse order of removal

The process may vary a bit between models. For more thorough instructions, find a model-specific tutorial.

Replacing the shock absorbers yourself will save you a lot of money on labor and replacement parts. In fact, we sell genuine OEM shock absorbers at rock bottom prices. Check out our catalog to see how much money you can save on replacement shock absorbers!