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Symptoms of a Bad Control Arm Bushing

Mia Bevacqua
April 4, 2018

As you drive, your wheels move up and down. Springs and struts help make this possible, as do control arms and control arm bushings. The following problems can be caused by one or more bad control arm bushings:

  • Noise: A knocking or thumping noise — especially when going over bumps — can indicate a bad control arm bushing. This happens because the worn bushing no longer holds the control arm firmly in place. Instead, the arm bangs around, causing a noise.
  • Tire wear: Worn control arm bushings can allow the control arm to shift from its intended position. This will create abnormal wear on one or both sides of the tire’s tread. 
  • Steering problems: Worn control arm bushings can greatly affect a vehicle’s alignment. This can make the car hard to steer, or give it vague, wandering steering. Bad control arm bushings can also make a car pull to one side.
Get it diagnosed by a professional
 

What are control arm bushings?

Control arms connect the car’s frame to the steering knuckles, which the tires and wheels are mounted on. As you go over bumps and potholes, the control arms pivot, allowing the wheels to move vertically.

Between the control arms and the car body are control arm bushings. These allow the control arm to move without excessive friction and help reduce vibration and noise. Typically, control arm bushings have a metal sleeve surrounded by rubber or polyurethane padding. A large bolt or pin goes through the center of the bushing to secure the control arm to the frame.

Each control arm usually has two bushings, one at each point where the arm mounts to the frame. Many front suspensions, as well as some rear suspensions, use control arms and bushings. 

» LEARN MORE: Get an accurate estimate for your car repair

What to do about failing control arm bushings

Faulty control arm bushings should be replaced. In some cases, the bushings can be separated from the control arm using a special tool, but if not, the entire arm will have to be replaced. Either of these jobs should likely be left to a professional mechanic, as the process involves lifting the car and precise placement of the new parts.

Some manufacturers insist that the control arm bushing fasteners be tightened with the vehicle at normal ride height. The manufacturer’s repair information should be followed to ensure the new bushings are installed correctly.  

We recommend replacing control arm bushings as a set when possible, especially on cars that are used heavily. 

After the bushings have been replaced, a wheel alignment should be performed.

 

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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