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How to Tell If Your Car Needs New Shock Absorbers (Good vs Bad Shocks)
Junky DIY guy
Overview
This video explains the function of shock absorbers and struts in a car's suspension system, detailing how they work to provide a smooth ride and maintain tire contact with the road. It then outlines five key signs that indicate these components are worn out: leaking fluid, excessive bouncing, significant body roll, unusual noises during acceleration or braking (like nose-diving or rear-end squat), and a shaking steering wheel. The video also touches on how to test for these issues and briefly mentions air struts and their common failure points.
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Chapters
- Shocks and struts are crucial parts of a car's suspension system, working with springs to ensure a comfortable ride.
- They maintain tire contact with the road, improving traction, steering, braking, and overall stability.
- Springs absorb impact energy, but shock absorbers control the spring's rebound, preventing excessive bouncing by converting motion energy into heat.
- Struts are integrated units combining a shock absorber with a spring seat and mount, sometimes featuring a rotatable mount for steering (McPherson struts).
Understanding how shocks and struts function is essential for appreciating their role in vehicle safety and ride comfort, and for recognizing when they are not performing correctly.
A basic shock absorber has a tube filled with oil and a rod with valves; as the rod moves, oil is forced through small holes, creating resistance and generating heat, which dissipates into the air.
- Worn seals in shock absorbers allow hydraulic fluid to leak out, which is a primary indicator of failure.
- Visible oil leaks, often accompanied by grime buildup on the shock or strut, signify a problem.
- Physical damage, such as dents or excessive rust on the shock absorber body or rod, can impede its movement and indicate failure.
Fluid leaks compromise the shock's ability to dampen movement, and physical damage can cause immediate and severe performance issues, both directly impacting vehicle control.
Observing oil leaking from the tube of a strut, with grime accumulated around the leak, clearly shows the strut is compromised.
- When shocks fail, they can no longer control the spring's rebound, leading to the car continuing to bounce after hitting a bump.
- A simple bounce test (pushing down on a car's fender) can reveal excessive bouncing if the car rebounds more than once.
- Excessive body roll, where the car leans significantly when turning, indicates worn shocks or struts that can't adequately stabilize the vehicle's weight transfer.
Uncontrolled bouncing and excessive body roll reduce tire contact with the road, decreasing stability and increasing the risk of losing control, especially during cornering or evasive maneuvers.
During a test drive, if the car continues to bounce for more than one cycle after going over a bump, the shocks are likely failing to control the springs.
- Worn front shocks can cause excessive 'nose-diving' during hard braking because the springs are not being controlled, shifting weight forward.
- This nose-diving can make front brakes less effective and increase braking distance, while also causing uneven tire wear.
- Worn rear shocks can lead to the rear of the car squatting excessively during hard acceleration, as the rear springs compress without damping.
These symptoms directly affect braking and acceleration performance, increasing stopping distances and compromising vehicle stability during critical driving situations.
During hard braking, if the car's front end dips significantly and stays low, it suggests the front shocks are worn and not controlling spring compression.
- When driving over rough surfaces, worn front shocks or struts can cause the wheels to bounce, leading to vibrations felt in the steering wheel.
- A persistently shaking steering wheel often indicates worn front suspension components that are failing to keep tires firmly on the road.
- This bouncing and lack of consistent tire contact can result in uneven tire wear patterns, such as 'cupping' or wear on the edges.
A shaking steering wheel is a direct indicator of compromised front-end stability, which can lead to unpredictable handling and premature, costly tire damage.
If the steering wheel vibrates noticeably while driving, especially over bumps, it's a strong sign that the front shocks or struts may be worn out.
- Air struts replace traditional coil springs with inflatable rubber bags, offering adjustable ride height and often a more comfortable ride.
- While the general signs of wear apply, the most common failure in air struts is air leaks.
- Symptoms of air leaks include one side of the car sagging lower than the other after being parked.
Understanding the specific failure modes of air struts is important for owners of vehicles equipped with this advanced suspension technology.
Spraying soapy water on an air strut and looking for bubbles indicates a leak, pointing to a faulty strut, air compressor, valve, or hose.
Key takeaways
- Shock absorbers and struts are vital for controlling spring movement, ensuring ride comfort, and maintaining tire-to-road contact for safety.
- Leaking fluid, physical damage, excessive bouncing, and significant body roll are clear indicators of worn shocks or struts.
- Unusual noises during braking (nose-diving) or acceleration (rear squatting) point to specific issues with front or rear shock absorbers, respectively.
- A shaking steering wheel, especially over uneven surfaces, suggests problems with the front suspension components.
- Regularly inspecting your vehicle for these signs can prevent decreased stability, increased braking distances, and premature tire wear.
- While the bounce test is useful for older cars, a test drive is more reliable for diagnosing modern vehicles with multi-stage valve systems in their shocks.
- Air struts have unique failure modes, with air leaks being the most common issue, often manifesting as uneven vehicle height.
Key terms
Shock AbsorberStrutSuspension SystemSpring ReboundHydraulic FluidBody RollNose-DivingTire CuppingMcPherson StrutAir Strut
Test your understanding
- How do shock absorbers prevent excessive spring bouncing after hitting a bump?
- What are the visual signs that a shock absorber or strut might be failing?
- Why is excessive body roll a concern when turning, and how does it relate to worn shocks?
- What does excessive nose-diving during braking suggest about the front shock absorbers?
- How can a shaking steering wheel indicate a problem with the car's suspension?