A control arm is a vital component of a car’s suspension system that carries out different functions, and you can find it in virtually all cars and automobiles.
It is also known as ‘A-arm or a wishbone due to its shape. Control arms are found in nearly every vehicle and automobile on the road.
In this article, we are going to discuss everything you need to know about the control arm, Its functions, and also how you can go about fixing this critical component of your engine when it gets bad.
This article aims to ensure safe driving and smooth rides because a bad control arm can affect both safety and drivability.
What Is The Control Arm On A Car?
The control arm is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel of a vehicle. The control arm allows a driver to direct the car’s movement and wheels on the road. Although they look simple, the control arm performs a huge function in enhancing the stability and drivability of a car
Control Arm Design
The design of control arms changes at the same rate as automotive design and manufacturing technologies.
Most vehicles feature a “double-wishbone” suspension, composed of upper and lower control arms shaped in the same way as a wishbone.
Control arms are also known as “A-Frames” or “A-Arms,” depending on whom you spoke to. Wishbones, which look similar to the letter “A,” is a type of bone found in birds.
Because this control arm shape and design works well, it is widely used in modern vehicles.
Types Of Control Arm
There are 3 types of control arms, the lower control arm, upper control arm, and adjustable control arm
1. Lower Control Arm
Lower control arms is used only if a vehicle has “MacPherson-strut front” or rear suspensions.
Hence, since the strut replaces it, it doesn’t require an upper control arm. In other words, an upper control arm is not needed, and there are no need for rubber control arm bushings.
2. Upper Control Arm
Any type of control arm can be used to connect the rear axle to a vehicle with a solid axle. You can often see about three to four control arms with rubber bushings at each side.
The upper control arm is also called ‘trailing arms’ and ‘rear-trailing arms.’ If the car has an independent rear suspension, it can feature trailing or upper & lower control arms.
3. Adjustable Control Arm
As its name implies, adjustable control arms are significantly used to adjust the wheel camber. The camber is the vertical alignment of the wheels.
A negative camber shifts the top of the wheel to face the center of the vehicle. On the other hand, camber is positive if the top of the wheel is positioned outside the vehicle’s center.
Adjusting a camber is very important, especially for racing, stance, and bringing down or high-jacking of a car.
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Bad Control Arm Symptoms
The following are some common bad control arm symptoms.
Whenever the control arm wears out, you’ll begin to experience vibration with the wheels. The wheels will also shimmy when reversing.
In other words, the steering wheel will vibrate when reversing. Once your steering wheel tingles, make sure you inspect the bushings immediately to check for possible damage.
There are also other parts of your car that can cause vibration. Therefore, before rushing to a conclusion, make sure that none of the other parts are involved since vibration is just one of the symptoms of a bad control arm.
2. Wandering Steering Wheel
One of the most significant symptoms of a bad control arm is a wandering steering wheel. The steering wheel moves from one side to the other with vibrating signs and faulty control arms maker aside.
If you encounter a wandering steering wheel, it indicates too much movement or worn-out bushings and ball joints.
Therefore, it is a sign that the control arm is faulty, and failure to change the defective parts as soon as possible will make the driver uncomfortable and make him lose control of his vehicle.
3. Unusual Noises
Unusual noise is one of the bad control arm symptoms. This sign is indicative of excessive wear of control arm bushings or ball joints.
Bushings help halt the control arm in motion, while ball joints help it rotate. If they are worn out, it could increase the movement and knock the metal components of the joint.
These activities will produce sounds in the suspension, particularly during acceleration, going around curves, or driving in challenging road conditions.
If a control arm is bad, it can cause a popping or snapping sound, or even a clicking sound whenever the vehicle comes to a halt.
At first, you might be tempted to ignore the sounds since they’re very minimal. However, if you do nothing about it, the noise will increase in its intensity and develop more bad suspension components symptoms.
4. Wobbly Wheels
Another symptom of a bad control arm is a wobbly wheel. If the wheel hub is bad or damaged, it can also cause the wheel to wobble.
Remember, a control arm connects the wheels and chassis to a vehicle. Therefore, the wheels will not rotate in a plane when they’re not connected to the chassis.
Again, a wheel will experience a wobble when the bushings are worn-out or if the control arm tweaks or bends. Driving at high speed while having a wobbly wheel is dangerous and affects your ability to drive.
5. Sudden Change in Braking
Even though it sounds strange, a bad control arm can improve braking performance, especially when you didn’t expect it to.
This symptom often occurs if the bushings become faulty and stop the control arm from moving back and front.
Nevertheless, it often improves temporarily and doesn’t happen every time you touch the brake pedal.
Failure to address the issue will cause dreadful brake performance, leading to driving insecurity. Therefore, you’ve to sort out the problem immediately when you notice it.
6. Steering Wheel Pulling To The Side
The control arm plays a crucial role in providing efficient steering and helps in the up and down movement of the vehicle’s body.
As a result, if it is faulty, it will not function properly, and the car will be pulled to one side while driving; at this point, you need to force it back in line.
Other parts could also cause this problem, for instance, if the control arm is damaged. Therefore, you need to check the control arms on each end for clarification. If the steering wheel is stiff, the ball joints are dry.
Lack of lubrication can also halt the free movement of the control arm, and it will cause difficulty in steering, which is a big problem regarding driving and safety.
Joint lubrication will solve the problem if the joint is not worn out and does not show any ill signs.
7. Uncomfortable Rides
The control arms are hinged on bushings which dampen vibrations and minimize the impact of bumps or rough terrain.
If these parts are bad, any passenger you are carrying will feel the gallops and potholes on the road.
Faulty control arms can make a vehicle lean very heavily at corners, especially sharp ones.
Whenever the car moves on from a fixed point, its rear will go through a backward movement, thus, giving you a sign that your control arm is bad and needs replacement.
8. Uneven Tire Wear
Several things can cause uneven tire wear, one of which is a bad control arm. When wear is detected on the inner edges, it indicates worn bushings or ball joints.
If a control arm bends or tweaks, it can cause uneven tire wear. Once there’s a little bend in a control arm, you’ll hardly spot it. But with the bushings or ball joints, it’ll be clear.
You can discover this through correct measurement. If your control arm or its hinges is bad, it could result in uneven tire wear. It could also affect the bushings or ball joints, indicating that the control arm has a problem.
Control Arm Replacement Cost
On average, control arm replacement costs between $120 and $200. Parts can cost between $50 to $100, and labor costs range between $80 to $150. This price range does not include taxes or fees and does not take into account your vehicle model and location. Other repairs might also be required.
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How To Replace A Bad Control Arm
Watch this video to see how you can replace control arm
The control arm is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel of a vehicle.
Control arms enable a driver to control the car and also guide the wheels along the road surface. Although they look simple, control arms play a crucial role in vehicle stability and drivability.
Although they may not be the most complex or fascinating components of a vehicle’s design, control arms are crucial to its operation.
These arms are designed to handle steering inputs from drivers and road surface fluctuations. They are essential to vehicle ride, handling, and drivability.