What is the control arm?

A control arm (or A arm) is an important suspension component that connects the wheel hub and steering knuckle to the frame (or chassis) of your vehicle. The inner end of the control arm attaches to the frame via a rubber bushing and the outer end connects to the steering knuckle by a ball joint. This allows for the control arm to flex according to road conditions. A perfectly functional control arm assembly will reduce the levels of vibration that are sent through your vehicle, resulting in a smoother, comfier ride.

Learn more about how control arms work >

Since control arms are usually made of high-grade steel or aluminium, they tend to last a long time. However, the rubber bushings and ball joints can be subject to wear over time. A worn bushing or ball joint can affect the comfort and stability of your car, making it unsafe to drive. For this reason, we recommend that you get the control arm assembly serviced sooner rather than later. The control arm itself can also become damaged in some cases, usually due to a sudden impact or extreme corrosion.

Your upper and lower control arm, the control arm bushes and ball joints all need to be in good working condition to pass a Warrant of Fitness (WoF). Play in the ball joint or worn / leaking control arm bushes may fail a Warrant of Fitness (WOF).

Please note: It is sometimes more cost effective to replace the whole control arm than to spend the labour on replacing individual parts such as the ball joint and control arm bushes.


Symptoms of a damaged control arm assembly:

  • Car pulling to one side – Worn ball joints or bushings can affect your car’s steering, causing it to pull to one side while you are driving. This will require constant correction from the driver, meaning that it can lead to an accident if you are not careful.
  • Vibrating steering wheel – Damage to the control arm assembly will cause increased steering wheel vibrations. In most cases, these vibrations will be most noticeable when you accelerate quickly.
    Vibrating steering wheel diagnostics in Hamilton >
  • Rattling Noise – a worn ball joint or very worn rear control arm bushes can sound like a dull rattle at lower vehicle speeds when going over non smooth roads.
  •  Clunking or grinding noises – If the bushings or ball joints become worn, they will often develop excessive play. This can lead to them clunking as they hit expand and contact while you are driving.
  • Problems with wheel alignment – If the control arm’s components are damaged, they can affect the alignment of your wheels.  This can affect your car’s ability to drive straight and increase your tyre wear, plus decrease your cars stability on the road.
  • Significant rust – if your car has been left siting for an extended period where grass and moisture have been allowed to surround the upper or lower control arms then you may notice the control arm has turn the orange / brown colour of metal rust. This can affect the control arms ability to pass a WOF.


Control Arm, Bushings and Ball Joint Replacement in Hamilton

Has your car failed a Warrant of Fitness (WOF) for your car’s control arm, bushings or ball joint(s)? If so, we can help! At Grimmer Motors, our skilled mechanics can inspect your control arm bushings or ball joint(s) for issues. Once we have diagnosed the problem, we can provide reliable, high-quality replacements that will last the test of time.

For control arm replacement, servicing and diagnostics in Hamilton, contact Grimmer Motors today!


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