Next, we let us discuss the different materials used in the manufacture of control arms and the up and downsides of each.
Control arms are important components in a vehicle. As we have seen, these auto parts ensure smooth driving and passenger or driver comfort.
Because they hold the wheels to the frame, they need to be sturdy enough. A broken or bent control arm is not desirable when driving. That means manufacturers have to choose control arm materials carefully. Not only that but also use the right manufacturing process. Control arms must be checked to satisfy different requirements. In this chapter of the control arm guide, we will look at the manufacture of control arms and the various materials used. Steel— this has been the main material for control arms in the history of vehicles.
Stamped steel was and still is used. Steel control arms cost less to manufacture. That means they can be mass-produced, and one of the reasons for their low price on the market. Steel control arms are inexpensive, a reason for a car owner to prefer them when replacing a bad one. Steel flexes under stress, which is an advantage when used for a suspension part. It means fewer cases of breakage or cracking of the control arm when off-roading or driving with heavy loads.
Steel control arms are also strong enough to be used on the average car. A major disadvantage of steel control arms is their inability to resist rusting. With these components hanging low and exposed to wet conditions and salts, rust is almost inevitable when steel used to make them.
That would mean reduced lifespan. In a rusted condition, the ball joint and bushings would present a challenge to remove. Steel also produces heavy components. Weight in the steering system parts can reduce the ease to handle a vehicle. Many car manufacturers strive to make lighter components today and the reason they may not use stamped steel control arms. Aluminum— using this material offers several advantages. Aluminum is lightweight. For the components that connect to the steering system of a vehicle, too much weight affects handling characteristics.
Aluminum control arms help to reduce weight, which results in easier steering. Aluminum control arms are made from cast aluminum. They are quite sturdy, a necessary characteristic for suspension parts. Some aluminum control arms can even be stronger than steel ones. Another major advantage of aluminum when used to manufacturer control arms is the ability to resist corrosion. Aluminum does not rust, which means a longer lifespan even when the components are subjected to extremely wet conditions.
A disadvantage of using cast aluminum is its reduced ability to flex under pressure. While control arms made from steel will bend if exposed to stress or impact, aluminum control arms would crack or break. Another disadvantage of aluminum is its soft nature that would cause accelerated wear, especially at the ball joint end. Cast Iron— cast iron is a popular material for the control arms used in most modern vehicles.
This material offers several benefits. It is sturdy, which makes cast iron control arms suitable for conditions where a lot of weight has to be supported.
That makes cast iron control arms the most used in trucks and SUVs. These types of control arms can withstand several other environments and driving conditions to give the component a longer life. Compared to steel, cast iron control arms are lighter. That means enhanced steering or vehicle handling. Bolt in— this kind of assembly uses bolts to connect the different parts of the control arm. MacPherson suspensions usually use bolt-in assemblies.
Bolt-in control arms allow dismantling of the parts. However, it also means more work. Unitized— in this control arm assembly, the control arm comes with a ball joint. Because the ball joint and the control arm form one part, you cannot replace only the control arm or ball joint.
It requires you to remove the whole assembly. These types of assemblies are better when it comes to replacing a bad one. You will not have many parts to remove, and the process takes a shorter time.
You can also use simple tools for the task. Press in— these are also integrated with a ball joint. Press-in control arms are commonly used in large vehicles. As the unitized type, press-in assemblies make replacing worn or damaged control arms easy.
Regardless of the material or assembly, a control arm will eventually age and go bad. Sometimes, it can be as a result of rough driving or accidentally hitting the wheels on something.
Control arm damage or wear can take many forms. It also happens to different parts of the control arm as we will see in the next chapter. Automotive control arms are simple components but which are prone to damage. Malfunction mostly happens at the control arm bushings and ball joint, and rarely the main body.
In such cases, replacing the affected parts solves the problem. But not all control arms allow the bushings to be replaced. Some come with built-in ball joints and require changing the whole assembly if the ball joint wears out. This chapter examines the different forms control arm failure as well as the causes. Problems are different for the different parts of this auto part.
Control arm bushings break down and cause the metal parts to come into contact. Ball joints wear down and produce excessive play. The main body may rust, bend or break to cause drivability issues. Let us look at the possible problem for each part. This happens if the component comes into contact with water or moisture over a long period.
Rust affects the structural integrity of a control arm. It also makes replacing the components at either end difficult. The body of a control arm may also crack, bend, or break under extreme conditions. These include collisions, excessive vehicle abuse, or the wheels hitting a curb.
A control arm can also damage if wrongly hooked when being towed. Control arm bushings damage— control arm bushings are mostly rubber and susceptible to breakage and wear. Over time and if subjected to extreme usage, the bushings can fail to allow the metal components of the suspension to touch.
Bad control arm bushings are loose and cannot restrict the movement of the control arm they are mounted to. They also do not absorb vibrations to dampen off the noise. That leads to rough rides and difficulties controlling the vehicle.
The vehicle makes unusual and annoying noises while driving. Control arm ball joint damage— at the end of control arms where they attach to the steering knuckle or wheel assembly mounts a ball joint.
Some control arms come with a built-in or permanent ball joint, while others use a separate joint. If the ball joint is permanently attached, its damage would mean having to replace the control arm. Ball joints, especially those of lower control arms, support a lot of weight. They, therefore, do wear out quickly. It can make vehicle control a challenge. Driving a vehicle whose control arm ball joint is faulty can even be a safety risk. These are situations that incline the component to rust, the bushings or ball joints to rapid wear, and extreme environments that cause breakage or bending.
The causes of a bad control arm include:. Going into drive and gas immediately after starting the car takes a toll on the suspension, particularly the control arm bushings and ball joint.
Having this driving habit causes rapid wear and breakdown on these ends of the control arm. If the bushings are the irreplaceable type and the ball joint built-in, it can mean having to install a control arm sooner than normal.
To avoid early damage, it is advisable to be gradual in transitioning from vehicle start to gas. In other words, accelerate gradually to allow the suspension to move in time with the car frame.
It improves the life of the control arm considerably. Bumps and potholes cause stress to the control arms. If the weight of the vehicle is always high and the road conditions rough, the effects can be control arms that break down before the usual lifespan.
It mostly damages the main body of the control arm by causing cracks and breakages. Severe road conditions also ruin the ball joints at the end of the control arms, and can even cause it to break free and become a driving risk. Avoiding rough conditions of the road is recommended. If impossible, it is advisable to drive over potholes and bumps slowly and carefully.
Moisture causes the surfaces of a control arm to rust. Over time, the rust wears off the metal and causes destructive corrosion. Moisture or water will also cause the protective dust boots of the ball joints to break down and allow the entry of debris into the joint. Dirt and debris are the main causes of accelerated wear and eventual joint failure. Water coming into contact with the control arm bushings would also cause damage that affects the usefulness of the component.
Water breaks down the rubber that makes the bushings. Every vehicle requires careful driving and handling to protect the various components. In the case of moving auto parts such as control arms, extreme care is necessary. Collisions would cause the arm to distort, the bushings to crack, and the ball joints to break down.
Some common rough driving habits include situations where the wheels hit a raised part of the road or parking, causing physical impact to the ball joints, bushings, and control arm. It can also be situations where you have to brake hard. Braking a speeding car suddenly puts stress on the control arm and its components.
During control arm installation, under-tightening of the mounting bolts is possible. Should that happen, any slight stress or strain on the component would result in excessive movement at the under-tightened ends. In the case of the ends that attach to the chassis, the movements would cause wear and damage to the bushings. On the opposite side, a loose mounting would lead to damage to the ball joint.
The frame of the control arm would not be spared either, and the possibility of cracks would be higher. As long as a vehicle is being driven, its control arms will eventually age and go bad.
Sometimes, damage can happen to relatively new control arms due to various reasons such as impacts. Luckily, a bad control arm will show signs.
The symptoms can be seen with the eyes, felt while driving, or even heard. In the next chapter is a list of these signs and an explanation for each. Except in situations where a control arm breaks or bends while driving, most faults show gradual signs. Knowing the symptoms of a bad control arm is an essential skill for a vehicle owner.
These components hold the wheels to the car frame, and their failure can compromise vehicle safety. Bad control arms can make rides a most uncomfortable experience, especially if driving on rough terrain. A driver would also struggle to control a vehicle whose control arms have gone bad. The ball joint is a steel ball enclosed in a steel socket that allows the spindle and front wheel to rotate left and right and allow the wheels to move up and down following the roads surface.
Sandwiched between the control arm and vehicle frame, positioned in a spring socket, is a heavy steel coil spring that supports the weight of your vehicle and provides a cushion against bumps.
To ensure that the control arms, bushings and ball joints are in perfect alignment, some control arms include adjustable attachment points at the frame. When necessary, a mechanic can align the front end and keep your car driving straight down the road.
Learn more about quality steering and suspension parts , find your car part , or find where to buy your auto part today. The content contained in this article is for entertainment and informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein.
Under no circumstances will we be liable for any loss or damage caused by your reliance on any content. The ball joint is a steel ball enclosed in a steel socket that allows the spindle and front wheel to rotate left and right and allow the wheels to move up and down following the roads surface.
Sandwiched between the control arm and vehicle frame, positioned in a spring socket, is a heavy steel coil spring that supports the weight of your vehicle and provides a cushion against bumps. To combine the two opposite motions on each end of the control arm, the arms are tied on the frame side to pivot up and down on the control arm bushings. On the opposite end, the control arm is tied to the spindle and front wheel with upper and lower ball joints.
The coil spring supports the weight of the car and dampens the shock of road surfaces. To ensure that the control arms, bushings and ball joints are in perfect alignment, some control arms include adjustable attachment points at the frame.
When necessary, a mechanic can align the front end and keep your car driving straight down the road. The control arm also makes the coil springs to respond to the axle and wheel assembly when treading through the bumps and potholes on road.
The pivots at the other end of the control arm allow for the up and down motion of the coil springs, helping them to absorb the shocks during bumps. The control arm in your vehicle synchronizes all the four tires to the motion of the vehicle to allow for a smooth and comfortable traveling experience. It also improves steering and reduces the tire wear-out with the less-traction contact surface as the rubber meets the road.
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