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How to Tell if You Have Bad Struts

Mia Bevacqua
May 24, 2018

Worn or damaged struts can make for an uncomfortable driving experience. Even worse, they can adversely affect other parts of your car, including the tires. Here are some symptoms to watch out for:

  • Noise while driving: A knocking or thumping noise — especially over bumps — can indicate worn struts. Bad front strut bearings may also cause a popping noise or a binding feeling when the steering wheel is turned.
  • Rough ride: Over time, struts lose their dampening ability, producing a bumpy ride and causing the car to bottom out. The nose or tail end of the vehicle may also dip down during hard braking and acceleration.
  • Body roll when turning: Worn struts may cause the vehicle to exhibit excessive body roll when you turn. This results in reduced steering and handling ability.
  • Abnormal tire wear: A “cupped” wear pattern in the tire tread is often a sign of bad struts. This happens because the struts are too weak to keep the tire in contact with the road. Extremely worn or damaged struts can also throw a vehicle’s alignment off, resulting in abnormal tire wear.
  • Fluid leaks: Struts are filled with hydraulic fluid, which can leak out when they begin to wear.  
  • Increased stopping distance: Bad struts can allow the vehicle to bounce around when braking, increasing the time it takes to stop.
  • Pulling and wandering: Damaged or extremely worn struts can hurt the vehicle’s alignment. This results in steering pulling and wandering.
Get it diagnosed by a professional
 

What are struts?

When you think about your car’s struts, you likely think about its shock absorbers, too. “Shocks and struts” go together almost interchangeably as a concept — but while they both provide dampening over rough road surfaces, they're actually different parts.

  • Struts are a structural part of the suspension system that support the weight of the vehicle. In many cases, struts are also part of the steering system, pivoting whenever the steering wheel is turned. For these reasons, struts can affect a vehicle’s alignment.
  • Shocks do not support the vehicle weight, nor are they part of the steering system. They only provide vehicle dampening by controlling spring and suspension movement.

Most vehicles today use a suspension component called a MacPherson strut, named after its inventor, Earle S. MacPherson. This type of strut combines a shock absorber and coil spring into one assembly. With this design, the strut supports the weight of the vehicle while also providing dampening over bumps. The strut also serves as a pivot point for the steering knuckle, which attaches to the wheel and tire assembly.

MacPherson struts are certainly the most common type, but there’s another design that pops up occasionally. It’s called a “modified” front suspension strut, and it forms a wishbone shape that connects to the lower control arm. This configuration allows for a low ride height and aerodynamic hood line.

» LEARN MORE: Get an estimate for your strut replacement

How to fix the problem

Before spending time and money to replace the struts, you should have a mechanic perform a thorough diagnosis. Other suspension components — such as bushings and mounts — can mimic strut problems.

Worn or damaged struts should be replaced in pairs — front or rear. The struts can usually be exchanged as an entire assembly with the springs (called “quick” or “easy” struts), or they can be serviced separately. 

We recommend replacing the upper strut bearings and bushings along with the struts, and getting a wheel alignment once the new parts are installed.

This is a job best left to professionals, since the strut assembly contains dangerous, high-tension springs. The mechanic will remove the old strut, possibly along with brake lines or other suspension parts that are in the way. He or she may remove the old strut from the spring and add the new strut to the spring. Once the new struts are in place, everything will be reassembled.

 

Mia Bevacqua

About the Author

Mia Bevacqua is an automotive expert with ASE Master, L1, L2 and L3 Advanced Level Specialist certification. With 13-plus years of experience in the field, she applies her skills toward writing, consulting and automotive software engineering.

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