Control Arms - Lower Control Arm - Upper Control Arm


Front Lower Control Arm - Rear Control Lower Arm - Control Arm Replacement

Suspension Control Arms, bushings, and ball joints may not be common household terms for many vehicle owners. You may have never even heard of them, but they are critical components of your vehicle’s suspension system that allow your tyres to be able to provide a smooth ride. A control arm connects the wheel hub and steering knuckle to the frame of the vehicle. They are typically equipped with bushings on the frame side of the vehicle and a ball joint on the wheel side of the vehicle that allows flex and controlled movement according to road conditions and steering input from the driver. 

 

What does a control arm do?

MacPherson Strut vs Double WishboneIn basic MacPherson struts common in modern cars, there is a lower control arm on each side. The inner part of the lower control arm is attached to the body or the subframe through rubber bushing to soften road noise and vibration. These bushings give pivot points allowing the control arm to swing up and down as the vehicle drives over bumps. The control arm's outer end connects through a ball joint to the steering knuckle; this is the part that carries the front wheel. A sway bar is attached to both the lower control arms or struts to keep the car stable when turning.

In most cars, a control arm has an A- or L-shape design, that's why it is also called an A-arm. While in some cars, a control arm is a single beam. If your vehicle has a double A-arms or double-wishbone layout, the steering knuckle is held by lower and upper control arms. This layout type is used in many large SUVs, pickup trucks, many high-end vehicles, and race cars. The upper control arm is smaller, and the lower control arm, which is larger, carries most of the load. Both of the control arms have a ball joint, although the upper one is often smaller. As the wheel goes over a bump, both arms swing up and down on rubber bushings following the wheel. In both layouts, control arms are essential components. If they fail, the safety of the vehicle is compromised.

 

When do the control arms need to be replaced?

The most common reason is when the control arm ball joint wears out, and it cannot be replaced separately. The ball joint usually comes with the control arm as one unit. If the ball joint is worn out, it can pop out, causing the vehicle to lose control while driving. This is why a car with a worn-out ball joint is unsafe to drive. Unfortunately, it is hard to notice if the ball joints are worn out. Your mechanic can check the control arm ball joints and other components during a regular service, but this can only be done when your vehicle is lifted on the hoist. 

Cracked or worn-out control arm bushings are another reason you will need a lower control arm replacement or control arm replacement. However, you can replace the bushing separately in many cars. Another reason for control arm replacement is when it has been bent or damaged after hitting a curb or pothole. 

 

What are the symptoms of a bad control arm?

  1. lower control armVibration on the steering wheel - One of the common symptoms of bad control arms is vibration on the steering wheel. If the control arm ball joints become worn out, it can cause wheel shimmy, which may cause the vibrations that the driver will feel in the wheel. These vibrations may increase as you accelerate but will smoothen out once you are travelling at speed.
  2. Steering wandering - If you have a bad control arm, you may experience steering wandering. Control arm joints that are excessively worn out will cause the vehicle's steering alignment to shift, causing the steering to pull left to right when travelling down the road. You will need to correct it to steer the vehicle straight constantly.
  3. Clunking noises - If the control arm's bushings or ball joints are loose, this can cause them to knock during takeoff or when travelling through rough terrain. These clunking noises will continuously get louder as the control arm wears or until it eventually breaks.
  4. Drive Comfort - When your control arm is failing, it is no doubt that you will experience constrained driving performance. The primary essence of a control arm bushing is to cushion against small bumps. If it is heavily damaged, it will become ineffective and will only result in vibrations throughout the drive. In some cases, if the control arm bushing is entirely worn out, the control arm's metal sleeves will begin to rattle, resulting in an unbefitting clunking sound from the front end, especially while reversing or turning.
  5. rear control armBraking - Another symptom of a failing control arm is a sudden change in the braking effect. This is often because the forward and backward oscillation of the control arm is lost due to bushing wear. If this situation prevails, it will result in an unstable break.
  6. Acceleration - If your vehicle is accelerating at a static position or experiences only backward movements, this could mean that the control arm is failing. A failing control arm can be also recognized for its speed, slow pace of turning and trembling to steer.
  7. Uneven tire wear - If your control arm is failing, the tire tread will have uneven wear. One of the functions of the control arm is to free up the tire's movement. When this does not happen, your vehicle will experience uneven wearing. 

However, these symptoms are often difficult to detect, especially when you have little to no knowledge about your motor vehicle's mechanism. That's why it is crucial to follow the maintenance schedule of your car. Having your car diagnosed by a mechanic at least once a year could help you spot those issues that would go unnoticed. 

 

How much does a control arm cost to replace?

The cost to replace a control arm isn't much, and it is not an overly expensive part of your vehicle. The control arm replacement price depends on the make, model, and year of your car. This will also impact what kind you'll need for your vehicle. The rear control arm of a Toyota Camry is not precisely the same as the Honda Accord's rear control arm. When it comes to replacing lower & upper control arms, the labour usually costs more than half the repair price. This isn't something you should be surprised about. Labour costs are generally more expensive than the part you're installing or replaced in your vehicle. 

FAQs

Is driving with a bad control arm dangerous?

Yes and no. If the control arm bushing is bad, it is not dangerous, but it can still hamper your driving experience. The control arm bushing cushions the car from vibrations, apart from allowing easy turns. If the whole control arm is bad, then driving with it can be dangerous. The ball joint could eventually snap, and it will be hard for you to control the vehicle. 

What happens when a control arm fails?

When your lower & upper control arm fails, you will be experiencing different symptoms. Your steering is wandering, the driving comfort is different, and you'll also hear clunking or popping noises. Your driving performance will also be affected. 

Can I drive with broken control arms?

Yes, you can, but it is not safe to drive with broken control arms. Make sure that you have your control arms replaced before trying to drive it again. This is for your safety and the safety of other drivers on the road. 

What happens if a control arm breaks?

The control arm bushing is responsible for absorbing the shock of road bumps. If it's broken or incapable of functioning, your vehicle will continuously vibrate when you're driving. It will also cause the control arm's metal sleeves to move uncontrollably, which creates annoying clunking sounds from the front wheel.

 

Control Arm Ball Joint - Control Arm Suspension

Why shop at Machter?

  • Automotive part specialist
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  • Wide range of aftermarket car parts
  • Distributed worldwide
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Machter brings you a wide range of control arm kits, lower control arms, front lower arms and upper control arms. If you have any questions, please get in touch with our friendly and knowledgeable team on (02) 7801 4933 or sales@machter.com.au

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