Car Shock Absorbers: What You Need to Know & Signs They Are Worn Out

Shock absorbers are an important part of your car’s suspension system as it functions to absorb the impact as you drive on uneven surfaces. By properly absorbing the shock and vibration from the road, your car’s shock absorbers and suspension system ensure a comfortable and safe ride for you and your passengers. That’s why it’s crucial to know how to look out for signs that your absorbers may be worn out and need replacing.

Shock absorbers

4 Things to Know About Your Shock Absorbers

When people talk about a car’s suspension, they’re usually referring to the shock absorbers. In the most basic terms, a shock absorber, or damper, is a tube containing a piston, hydraulic fluid, and occasionally high-pressure gas. These components work together to ensure a smooth ride, among other things. Below are some things you should know about shock absorbers.

1. Function of a Shock Absorber

The shock absorbers absorb vibration and control the up/down movement of the shock springs. When the car wheel hits a bump, the fluid dampens the impact on the piston and smooths the movement of the piston and spring as they return back into place. This is important as it:

  • Ensures the tire is always in contact with the surface of the road.
  • Provides optimal brake performance.
  • Prevents the vehicle from bouncing or swaying excessively.
  • Ensures optimal steering response.
  • Ensures a smooth, comfortable, and safe drive.

2. How Long Do Shock Absorbers Last?

Like every car part, shock absorbers are prone to fatigue and wear. Therefore, it’s always important to pay attention to the quality of your ride and have your shock absorbers checked regularly. The lifespan of a shock absorber depends on several factors including your car’s mileage, your driving style, road conditions, and more. But in general, shock absorbers are considered consumables, just like your car’s tires and brake pads. Thus, it’s a good idea to have them looked at around the 30,000-kilometer mark, and replaced at 50,000 kilometers.

Read More: When Should You Get A Wheel Alignment and Balancing

3. Types of Car Shock Absorbers

The two main types of shock absorbers on the market are hydraulic oil absorbers and gas-charged absorbers.

Hydraulic Shock Absorbers 

A hydraulic shock absorber comprises a working cylinder or tube, a compression chamber containing air, and a piston rod that directs the hydraulic fluid (oil). It provides good performance on paved roads and under normal driving conditions making it suitable for regular passenger cars. On challenging surfaces and during extended aggressive driving, the oil in the shock absorber can start to boil and form bubbles which is called cavitation. Cavitation causes the viscosity of the hydraulic fluid to change which reduces the absorber’s performance.

Gas-charged Shock Absorbers

A gas-charged shock absorber has the same structure as a regular hydraulic one but has pressurized nitrogen gas instead of air in the gas chamber. The nitrogen gas compresses the oil which prevents cavitation, foaming and bubble formation, ensuring more consistent performance. Gas-charged absorbers are suitable for heavy and commercial vehicles, as well as sports cars that require nimble steering at high speeds.

4. Gas-Charged or Hydraulic Shock Absorbers?

Gas-charged shock absorbers are getting more easily available, but should you get it for your car? Here are the differences between regular hydraulic oil shock absorbers and gas-charged shock absorbers.

Differences Hydraulic Absorber Gas-charged Absorber
Price Affordable More expensive
Vehicle Type Suitable for regular passenger cars Suitable for heavy and commercial vehicles, as well as sports cars
Gas Chamber Filled with air Filled with pressurized nitrogen gas
Cavitation (risk of hydraulic fluid foaming) More likely to happen on rough terrain, causing a drop in performance  Less likely to happen, leading to consistent performance
Comfort The absorber is softer, leading to better comfort The absorber is stiffer, leading to a stiffer ride
Handling Adequate handling for normal driving Better handling at high speeds, eg. at the race track

signs of faulty shock absorbers

6 Signs of Worn or Faulty Shock Absorbers

A worn shock absorber will not only cause a rough, uncomfortable ride, it will also negatively affect the vehicle’s handling and braking performance. Furthermore, it could cause other components such as the tires and brakes to wear out prematurely. Here are the signs that you may have worn out shock absorbers.

1. Vibrating Steering Wheel

It’s normal for your steering wheel to vibrate when you drive over potholes or uneven surfaces. However, excessive vibration is a sign that your shock absorbers are worn out and can’t dampen the vibration well enough. If your steering wheel vibrates even on a smooth, level road, your shock absorber could be significantly worn or damaged.

Besides on uneven surfaces, you may also experience excessive vibration when driving on the highway at speed. Having to control a vibrating steering wheel is not only uncomfortable but it may limit your ability to steer your vehicle which could lead to an accident.

2. Your Vehicle Shakes or Sways While Driving

With worn shock absorbers, the shock and vibration that your tire absorbs will also be transferred to the whole vehicle. As a result, your car might vibrate, bounce, or sway excessively, making it feel unstable on the road. This problem is usually intensified when you drive at high speeds. If your shock absorbers are significantly worn out, your car could bottom out when you drive over bumps and dips which can further damage your suspension system.

3. Your Vehicle Rolls or Sways Excessively in Corners

One function of the shock absorbers is to ensure your car body stays in a neutral position when cornering. If you have a worn or faulty shock absorber, it can lose its ability to control the weight transfer rate when the car is cornering. This will increase body roll when you take a corner, especially at high speeds. It may also result in your car needing an increased steering input even when turning at low speeds.

4. Uneven Tire Wear

When your car bounces due to worn-out shock absorbers, it can put more pressure on your tires and accelerate the wear on them. A common type of tire wear caused by worn-out absorbers is cupping or scalloping. This refers to when you have high and low tread wear in random spots.

The worn parts are usually three to four inches in diameter and can cause a rumbling noise at high speeds or a harsh ride at lower speeds. If you notice cupping or scalloping on your tires, be sure to get your shock absorbers checked immediately.

5. Excessive Nose Dive and Squat

Properly functioning shock absorbers stabilize the movement of your suspension when you brake and accelerate. When your absorbers are worn out, your car’s front end could dive while braking and the rear end could squat during acceleration. This is a serious issue as it can increase your stopping distance and place an excessive load on other suspension components.

While it’s not advisable to try it out on the open road, you can pay attention to how your car reacts under hard acceleration and braking the next time you drive. Alternatively, you can push down hard on the sides of your car. If it bounces several times before stopping, it’s a sign of worn-out shock absorbers.

6. Fluid Leak on the Shock Absorbers

A sure sign of a faulty or worn-out shock absorber is when it’s leaking fluid. If the seal is worn out, hydraulic fluid could leak out and reduce the performance of the shock absorber. Dirt can also enter into the tube and affect the ability of the piston to move as intended. 

When you replace your faulty shock absorbers, it’s advisable to check the condition of your coil springs as well. If the spring has changed shape or lost its elasticity, you should replace it.

Read More: What Is a Car Engine Overhaul and When to Do It

Signs of Worn or Faulty Shock Absorber Mounting

The shock absorber mounting, also called the top strut mount or shock mount, is the mount that connects the strut or shock absorber to the vehicle’s body or frame. Besides ensuring the shock absorber stays in place, the mount also absorbs shocks, vibrations, and noise, preventing them from entering the cabin. The shock absorber mounting generally doesn’t require maintenance but does need replacing if it’s worn out. Some signs of a worn-out absorber mounting are:

  • Squeaking, knocking, or clunking sounds when you drive over bumps or maneuver at low speed. Sometimes there may be noises when you turn the steering wheel while stationary.
  • Visual signs such as signs of corrosion, tears or cracks in the rubber, and separation of the mount’s rubber and metal parts.
  • Excessive vibration, uneven tire wear, and poor steering return.

The shock absorbers and absorber mounting are important in ensuring your car’s suspension system is able to function properly. Without them, you could have a very bumpy and dangerous ride, so if you notice any of the warning signs above, be sure to have your car checked immediately. 

If you’re looking for a safe and comfortable pre-owned car, check out CARSOME. We put all our cars through a 175-point inspection to ensure they are free of major accidents and flood damage. We also check that the suspension, including the shock absorbers are in good condition as part of the 175-point inspection. Thus, the cars that pass our strict requirements are CARSOME Certified for your safety and comfort. Plus, they come with a five-day money-back guarantee and a one-year warranty from CARSOME for even more peace of mind!