The control arm is one of the most common components you’d find in just about any car you see around.
It is so common in most cars because it guarantees safe driving and smooth rides. On the flip side, a faulty control arm will affect your driving experience, which is why you need to understand what bad control symptoms are.
Understanding when your control arm has gone bad can save you from a car crash or expensive repair fixes.
In this article, we will be looking at how control arms work, the types of control arms out there, the symptoms of bad control arms, and the implication of not getting them replaced, among other things.
If you have been looking for information about your car’s control arms, then this is just what you have been looking for.
What Is a Control Arm on a Car?
A control arm is a critical component of a vehicle’s steering/suspension system. This component is affixed to an outboard-mounted hub at one end, and a vehicle’s frame at its opposing end.
Bushings are positioned within a control arm’s frame mounts, thereby preventing excessive wear under continuous movement.
A vehicle’s control arms allow each front wheel to move vertically, in retaliation to the vehicle’s frame.
This movement is cushioned via the use of specialty shocks/struts, which provide a ride free of harsh vibration. At its outer end, a control arm is connected to its corresponding wheel hub via a pivoting fixture, known as a ball joint.
Many trucks and SUVs feature both upper and lower control arms, which operate in tandem to secure the hub to which they are affixed.
On the contrary, some sedans feature only lower control arms. The exact dimensions of a control arm often differ from one model of vehicle to the next.
Types of Control Arms
The control arms are at the heart of the front suspension system of cars because they serve as the link between the front wheels and your vehicle.
Although they come in different shapes and sizes, they are all designed to attach to the wheel assembly and the car’s framework simultaneously. Here are the types of controls arm:
#1. Lower Control Arms.
This is the kind of control arm you find in cars with a MacPherson strut style front or rear suspension. With such vehicles, an upper control arm isn’t needed since the strut serves its function. It is important that you understand the symptoms of a bad lower control arm.
#2. Upper Control Arms/Trailing Arms.
This is the type of control arm used in cars without the strut suspension system. They can be used for both the front and rear wheels of a vehicle, although they are primarily used for front-wheel systems.
It often consists of upper and lower arms that have rubber bushings attached to each end. It is also important that you understand the symptoms of a bad upper control arm as well.
#3. Adjustable Control Arms.
This kind of control arm is used to adjust the vertical alignment of the vehicle’s wheels. It is crucial to ensure that the wheels are well aligned, especially when racing, balancing, and lifting a car is involved.
For instance, adjustable control arms come in handy when a lift kit is installed on a vehicle. They ensure the wheel is well aligned so that the tires have the proper traction.
What do control arms do?
Control arms, also known as A-arms, are crucial components of your vehicle’s suspension system. They connect the wheel hub and steering knuckle to the frame or body of the vehicle. Here’s an overview of their function:
- Handling Vehicle Motion: The primary job of the control arm is to handle the motion of the vehicle up and down and allow the wheels to move independently of the car’s body. Essentially, the control arm absorbs the bumps and variations in the road, ensuring a smoother ride.
- Maintaining Correct Alignment: They also play an important role in maintaining wheel alignment. When your vehicle turns a corner, the control arm pivots, allowing the wheels to move up and down. By doing this, they maintain the correct alignment of your vehicle’s wheels during suspension travel (up and down motion).
- Supporting Suspension Components: Control arms also provide a mounting point for the vehicle’s suspension components, such as the shocks, struts, and springs.
- Stability and Comfort: The control arms, in combination with the suspension system, help maintain stability and comfort while driving. They help reduce the transfer of vibration and noise from the road to the cabin, making the drive more comfortable for passengers.
It’s important to keep control arms in good working condition. If they wear out or become damaged, you might notice symptoms like clunking noises, vibrations, wheel alignment issues, or uneven tire wear. These signs suggest the control arms, bushings, or ball joints may need replacement.
Control Arm Bushing Location
The Control Arm Bushing is located on the control arm, bolted on the vehicle frame side. The control arm is the arm located at the bottom of the suspension in the front suspension. If you have a 4WD, you may also find it in the rear suspension, depending on the suspension type.
What Causes Control Arms to Wear Out?
As mentioned, control arm is primarily composed of three main parts: body, bushing, and ball joint.
While it’s possible to analyze each of these components separately, the wear and tear on control arms are often interrelated. Therefore, we will provide a unified introduction to the reasons that contribute to the control arm damage.
#1. Uneven Road Surfaces and Impact.
Excessive bumps on the road can subject the control arms to excessive impacts. This not only causes deformation and bending of the control arm body but may also lead to damage to the ball joint.
#2. Prolonged Overloading.
While the main weight of the vehicle is supported by the springs, prolonged overloading can still place the control arms frequently in positions not originally designed for. This can result in excessive wear on the ball joint and body of the control arm.
#3. Neglecting Maintenance.
As a safety component, control arms are not prone to outright failures such as fractures. During maintenance, technicians often only check the smoothness of the bushing and ball joint but frequently overlook deformations in the body of the control arm. This oversight can often lead to difficulties in wheel alignment.
#4. Poor Parking or Driving Conditions.
- Deserts and other high-temperature regions
- High latitude extreme cold regions
- Saline-alkaline or snowy areas
- High humidity or coastal areas
All of the above driving environments can lead to corrosion and erosion of the control arms. To keep the control arms in optimal condition, it is advisable to avoid exposing the vehicle to such environments as much as possible.
#5. High-Speed Passage over Uneven Road Surfaces.
When a car passes over a pothole at high speed, the control arm experiences a sudden downward force, subjecting the bushing and body to impact.
Upon leaving the pothole, the difference in elevation between the road surface and the control arm creates a scenario akin to hitting a wall, causing the metal sleeve and body of the control arm to endure a force opposite to the vehicle’s moving direction.
This can result in damage to the connection points of the bushing or deformation of the control arm body.
#6. Poor Design.
Based on experience, the control arms of certain vehicle models may have a shorter lifespan compared to others.
In such cases, it raises suspicions that engineers may have overlooked certain factors during the suspension design, resulting in insufficient strength or excessive pressure on the control arms.
This leads to a significantly shorter replacement interval for the control arms of that particular model compared to others.
Bad Control Arm Symptoms
Despite its importance to the functionality of your vehicle, the control arm is a mechanical component, after all.
So it is liable to fail or go bad sooner or later. Driving around in a car with a bad control arm is not a great idea, so you want to replace the control arms as soon as you notice they have gone bad.
But how do you know when the control arms have gone bad. Thankfully, certain symptoms should tip you in that direction. Here they are:
#1. Vibrations of the Steering Wheel.
This is one of the most apparent symptoms of a bad control arm. What happens is that the worn control arm bushings often generate wheel shimmy. The wheel’s vibrations often get more intense when you step on the accelerator but ease out at cruise control speed.
#2. Steering Wheel Wandering.
The control arms are designed to affect the efficient movement of the steering of your car. If you notice that your vehicle’s steering wheel moves from side to side, you might have an issue with the bushings or ball joints of your car’s control arm.
Check the cars’ control arms as soon as you notice this symptom because you might risk yourself and other road users if the issue is not quickly resolved.
#3. Unusual Noises.
You are bound to hear unusual noises like popping or clunking noises when the bushings and ball joints of the car’s control arm have issues.
Once they are worn out to a certain degree, they fail to regulate the control arm’s movement, which causes the metal components to make popping and clunking noises. This is one of the more common jeeps xj bad control arm symptoms.
#4. Shaky Vehicle Wheels.
When the control arms fail to keep the vehicle’s wheels firmly connected to the car, you are bound to experience this symptom.
Control arms fail to stabilize the car wheels when the ball joint and bushings are worn, or the control arms are bent. When this happens, the alignment of the wheel is affected, and the wheels start shaking.
#5. Bumpy Rides.
Control arms that are correctly set up reduce the harshness of bumps while driving. Whenever any of its parts go bad, its shock-absorbing function is hampered, and the bumps become more troublesome when you encounter them.
You might also notice that the car leans a lot at sharp corners. If you notice any of these symptoms, you might want to check the control arms.
#6. Uneven Tire Wear.
Driving with bad control arm bushings can cause this symptom. When the bushings and ball joints get worn to a certain degree, it can affect the wheel alignment. This causes uneven tire wear because the edges of the tire start to wear off simultaneously.
Control Arm Replacement Cost
The cost of replacing your vehicle’s control arms will depend on several factors, including your vehicle’s make, model, and year, and the type, design, and material of the control arms. If you aren’t planning on replacing it yourself, expect to pay for labor as well.
At CarParts.com, aftermarket control arms can cost anywhere from $2.30 to $3,176. They can be purchased individually or in sets.
Meanwhile, replacement parts by original equipment manufacturers are typically only available at dealerships and can cost around 60 percent more.
If you’re planning a do-it-yourself control arm replacement project, you’ll only need to spend on the replacement parts, related hardware, and any tools that you don’t have on hand.
How Long Do Control Arms Last?
Control arms are purposefully designed and manufactured to last – often for the entire span of your vehicle.
In fact, many control arms last for up to or more than 100,000 miles. However, some situations can cause the control arm to go bad – like a collision or corrosion.
Impacts – like an accident with another vehicle, hitting a pothole, or hitting a curb – can lead to wear and tear on the control arm. Corrosion from road salt, severe weather, or other environmental elements can also lead to rusting and premature failure.
How to Diagnose a Bad Control Arm?
To start, you’ll need to raise your vehicle and look for parts like a worn ball joint, tie rod, or control arm bushing. Checking these components requires technical knowledge and expertise, so you should call an auto repair mechanic.
Here’s how they’ll perform the diagnosis:
- Visually inspect the control arm for cracks or rust accumulation.
- Look for tears or cracks on the bushings.
- Check the ball joints for torn boots or grease leaks.
- Inspect other steering and suspension components for any issues.
- Place a pry bar on the control arm near one of the bushings. Use the bar to push and pull the control arm downward to check its movement. If the movement is more than 1/8 of an inch, it indicates excessively worn bushings.
Solutions for Control Arm Problems
In order to extend the lifespan of the control arms and maintain optimal performance, preventive measures are crucial.
#1. Check the Control Arms During Maintenance.
During vehicle maintenance, pay special attention to the condition of the control arms. Through visual inspection, examine whether the dust covers of the ball joints are cracked or brittle.
The ball joint is a relatively precise component with high surface finish requirements. A damaged dust cover may allow foreign particles to enter the ball joint and cause damage. Additionally, check if the rubber portion of the bushing still retains its color and elasticity.
#2. Avoid Driving on Poor Road Conditions.
Crooked surfaces and extreme weather conditions can accelerate the wear and tear of control arms.
#3. Avoid Aggressive Driving.
Maneuvers such as drifting, rapid acceleration, and hard braking can subject the control arms to excessive stress. If you want to keep the control arms in good condition, it’s advisable to refrain from engaging in these behaviors.
#4. Drive Slowly on Bumpy Roads.
When encountering uneven road surfaces, it’s important to drive at a slow pace.
#5. Wheel Alignment.
Proper wheel alignment is crucial, as incorrect alignment can subject the control arms to prolonged stress. Good alignment can effectively reduce uneven pressure on the control arms.
#6. Consider Replacing Your Control Arms When Needed.
The typical lifespan of control arms is around 8 years or 80,000 miles. Depending on usage, this lifespan may be even shorter.
Exceeding 8 years or 80,000 miles indicates significant aging of the control arms, especially the ball joints and bushings. In such cases, it’s advisable to replace your control arms.
Installing new control arms can provide you with a significantly solid and confident chassis feel.
Driving your vehicle with the new control arms feels like it’s in the condition it was when it left the factory, without any loose or unstable sensations. This kind of effect is often unexpected before the replacement!
Additionally, in some models, the ball joints and bushings can be individually replaced, allowing you to address specific components before the overall structure undergoes deformation.
How to Prevent Control Arm Damage?
Preventing control arm damage is possible with a few proactive steps. Maintaining these essential components will help you avoid unnecessary repair costs and improve your vehicle’s safety and performance.
Regular Inspections
One of the best ways to keep your control arms in good condition is to have them inspected during routine vehicle maintenance. Look for signs of cracks or wear in the bushings or ball joints, and ensure there is no visible damage to the arm itself.
Drive Carefully
Avoid hard driving conditions, especially over bumpy or uneven roads. If you can, steer clear of potholes or construction zones, as these can cause significant wear on the control arms.
Proper Wheel Alignment
Keeping your wheels properly aligned is crucial to maintaining the health of your control arms. Misalignment puts additional stress on the suspension system, leading to premature wear.
Replace Worn Components
If you notice any signs of control arm damage, such as noise or handling issues, don’t wait to get them replaced. Keeping control arms in good condition ensures that your suspension system works effectively, maintaining both ride quality and safety.
FAQs.
Q: Can you drive with bad control arms?
You can, but it is not a great idea because driving a vehicle with a bad control arm is unsafe.
The reason is that bad control arms make the steering wheel unpredictable to use, and this makes you a hazard to yourself and other road users because you could be driving in an unsafe manner that puts everyone at risk.
So is driving with a bad control arm dangerous? Yes, it is.
Q: What happens if the control arm breaks while driving?
You will be in a precarious situation because you might lose control of the car. A broken control arm could lead to wheel alignment issues and possible loss of control of the car’s wheels.
This situation happens because the wheel is no longer stable. It is a difficult situation to be in.
Q: How long do control arms usually last?
It depends on how the vehicle is used, but by and large, they can last for between 90,000 and 100,000 miles if the car is used right and there are no adverse situations like accidents or frequent entry into potholes.
Constantly entering large potholes or any form of vehicular accident will reduce the longevity of the control arms.
Q: Are control arms hard to replace?
It depends on who is doing it and your vehicle’s makes and model. It might be difficult for a DIY proponent without the right tools and technical know-how, especially when there is some rust or corrosion of the car’s suspension.
A professional will make light work of replacing control arms. That said, in situations where the process is straightforward, like simply uninstalling an old control arm and replacing it with a new one, it should not be a difficult task.
However, some vehicle manufacturers design their vehicles in a way repair jobs are more easily accessible than other vehicles.
Q: Should you replace the lower control arm?
Not really. The thing is, it is not compulsory to replace both lower control arms if one is bad. In most cases, they wear off at about the same time.
If you find yourself in a situation where one has gone bad and the other hasn’t, you can replace the damaged one and walk away if you are on a tight budget. If you have the money, you still replace them.
Q: Is it OK to replace only one control arm?
It depends on the state of the other control arm. The thing is, in most cases, they wear off at the same time.
If they don’t, then one of them might not be far off. In most cases, it is not a good idea to replace only one control. Except you are on a tight budget, it makes sense to replace both if one is bad.
Q: Do I need an alignment after replacing the upper control arm?
Yes, you do. It would be best to get a wheel alignment after doing a significant task like replacing the upper control arm.
Upper control arms are often used in the car’s front suspension where the steering wheel is located, and any work done there can affect the wheel alignment.
Final Words
Your car will not offer the same driving experience when the control arms have gone bad. This is because functional control arms provide smooth rides and efficient control, among other things.
A bad control arm offers the exact opposite, so you need to be able to identify bad control arm symptoms. Hopefully, at this point, you have gotten some insights on how to detect these symptoms.