Control Arm Manufacturer

Some call it a control arm others wishbone or A-arm. But what are control arms in a car? To find out, read on. We explain what the component is in this guide, what it does, and the problems that cause it to malfunction. To help to identify the best control arms, we also have a section about the features to consider.

Control Arm Definition: what is a control arm?

It’s not often that you hear about them. Control arms are mostly overlooked, and when mentioned, go by different names. Despite that, you will find them in every car, truck, or SUV on the road today.

A car control arm is the component that attaches the steering knuckle to the vehicle frame. It’s also sometimes called a wishbone or “A” arm. Although designs and shapes vary, the typical control arm is a metal frame with connection points at either end.

One side of the control arm attaches to the car frame, while the other end connects to the steering knuckle. On the car chassis, these arms mount on a hinge-like connection using bolts and bushings. On the wheel side, a ball joint attaches the arm to the steering knuckle.

The control arm of a car or truck can be different shapes. Some look like an A, others an L, among other designs. There are also arms that are single shafts. Generally, manufacturers design the component to suit vehicle suspension geometry and other requirements.

The number and position of the control arm in a car or truck also varies. Some vehicles have two arms on either side, while others only have one. Those with independent rear suspensions have control arms in the rear as well. A car rear control arm can be any design or shape.

Control Arm Function: What Does a Control Arm Do?

The control arm connects the wheel to the frame via the steering knuckle. That way, it stabilizes the vehicle and allows the frame to move with the wheels. The arm also provides the pivoting point for the steering system through a swiveling ball joint. This helps to ensure proper coordination between the suspension and steering systems.

The control arm purpose in a car can, therefore, be summarized as:

1. To link the suspension to the wheels and allow the two to move in unison for comfortable rides.

2. To help keep the wheels in contact with the ground and stabilize the vehicle for safe driving.

3. To make steering a vehicle smooth and effective by providing a pivoting point for the steering knuckle.

As you can guess from the functions, the control arm must overcome many forces when a vehicle is in motion. It, therefore, should be made from tough materials. The component must also withstand corrosion, seeing that it’s always exposed and in the lower part of a vehicle’s frame.

Types of Car Control Arms on the Market

There are many versions of the control arm today. Based on the differences, we can classify the control arms on the market today according to design, material, and shape.

Based on Material

Throughout the history of the auto control arm, different materials have been developed with the aim of producing sturdy components. Today, car owners have a choice of three main material options, as explained below.

• Stamped Steel Control Arms

For a long time, stamped steel has been a common material for control arms. Steel offers the advantages of strength, low cost, and flexing under weight. The disadvantages of steel control arms include rusting. When used in wet conditions, they may not last for long. Steel also produces heavy arms, which is not desirable if several have to be installed in a compact car.

• Cast Iron Control Arms

Cast iron is another common control arm material. Many modern control arms are made from it. The material offers the advantage of sturdiness and the ability to resist damage . As a result, these types of arms are popular in trucks and SUVs where there are large forces to overcome. Cast iron also withstands corrosion and wear, making it longlasting in different driving conditions.

• Cast Aluminum Control Arms

This material produces lightweight control arms that suit applications that require light parts. Cast aluminum can stand up to the stress that suspension components are usually subjected to. It also resists rust, making aluminum arms to last a long time. Aluminum has its disadvantages, though. It’s a soft metal that wears easily. When used to make control arms, it can mean a shorter lifespan for the component. Cast aluminum also does not bend. Impacts are, therefore, likely to break or crack an aluminum control arm.

Based on Design

The control arm is one of the most varied vehicle parts in terms of size and shape. It exists in many different designs. Because control arm design produces distinct differences, we can group the component by that. The different constructions include the following.

• Unitized

These types of control arms come with a built-in ball joint. The joint can be other sealed or greasable. Unitized bolts are easy to install as there’s only a few parts to work on. However, they can be quite expensive to replace. That’s because you have to discard the entire assembly for a new one. Many aluminum control arms are this type.

• Bolt In

Bolt-in control arms use a bolt fastened joint. You will mostly find them in a Macpherson’s type of suspension and commonly made of a stamped frame. If you replace the ball joint of these arms, it’s usually necessary to ensure wheel alignment.

• Press In

As the name suggests, these use a pressed-in ball joint. To enable a tight fit, the joint is usually larger than the mounting bore or opening on the arm. Press-in arms most common in large vehicles such as trucks and SUVs. You need special installation tools to mount the ball joint on them.

Adjustable Control Arms

These arms are designed with the ability to alter installation positions. This allows the setting of caster angle, camber or pinion angle. They can be single beams with an adjustable length or triangular frame with a movable ball joint, among other constructions.

Adjustable arms are commonly used when installing a lifting or lowering kit. That is because the adjusted height affects alignment. Also, when you install an aftermarket control arm to replace a stock model. Some aftermarket arms may not fit the exact geometry of your suspension, requiring the adjustable type to calibrate caster angle.

Upper and Lower Control Arm

The car lower control arm links with the steering knuckle at the lowest point, the upper arm at the highest point. If your car uses the modern Macpherson’s suspension system, it only has the lower control arms. The place of the upper arm is taken by the strut.

High-end cars, SUVs, and race cars mostly use double wishbone suspensions. As you can tell, there will be two control arms (upper and lower) that link the chassis to the wheels. Usually, the upper wishbone (or control arm) is designed shorter than the lower arm.

Parts of a Control Arm

Control arm Assemblies are generally simple structures that consist of three main parts. That does not make them inferior technically. A lot of engineering goes into designing these vehicle parts to ensure the right size, weight, structural integrity, and more. The three main control arm parts are:

Main Frame or Body

This is the largest part of the arm. It extends from the frame where the arm attaches to the vehicle frame to the position where it mounts on the steering knuckle. The frame in today’s control arms comes in different shapes. That’s because engineers are continually researching different designs for the arm. The most common is the “A” shape.

Ball Joint or Ball Joint Bore

The outer end of a control arm assembly connects to the steering knuckle using a ball joint. Many arms come with the ball joint already installed, others without. The control arm ball joint pivots the steering knuckle, allowing it to turn the wheels while a vehicle is in motion. Control arms that feature an integrated ball joint make installation tasks easy. However, it also means you cannot replace either component as a single piece.

Bushings

Control arms hinge on the frame of a vehicle using bolts and bushings. Control arm bushings prevent metal to metal contact as the arm moves up and down with the wheels. The bushings also absorb vibrations, reducing noise and making rides comfortable, among other functions.

Control Arm Problems

The control arm on your car, just like any other suspension part, is designed to withstand damage, corrosion, and wear. However, it will not last forever. It eventually goes bad to the point of requiring to be changed. Common problems include the following.

Control Arm Frame Damage

This can range from rusting to bending or breaking. Rust occurs when the control arm assembly is exposed to water, especially if driving conditions are often wet. Bends or breakage often happen when the arm is made from a weak material or of inferior quality. Control arms rarely bend or break, unless there has been a forceful impact such as a collision.

Control Arm Bushing Damage

Control arm bushings and ball joints are more prone to wear and tear than the frame. That’s because the arm pivots around these parts every time you drive your car. Bushings reduce vibrations for smooth and quiet rides. If damaged, your car may not be comfortable to ride in any more. Bad control arm bushings can be replaced. However, many people opt to replace the arm instead.

Control Arm Ball Joint Damage

The control arm ball joint contains moving parts. This means a high rate of wear for the part. The joint may be either sealed or greasable, removable, or built-in. Serviceable joints allow you to keep the moving parts lubricated for a long time. Removable joints allow you to change the worn part instead of the entire control arm.

OEM or Aftermarket control Arms

Some car owners will buy OEM control arms others aftermarket models. What are the differences between the two and which type is better? The answer is, it depends on your preferences and ride requirements.

OEM control arms will usually fit your vehicle manufacturer specifications. However, it may not perform or even last as per your expectations. While some OEM arms outlast aftermarket models, most aftermarket’s are designed to offer superior qualities that match car owner needs.

If looking to improve various aspects of your car’s current handling performance, you may want to consider an aftermarket arm. These also often offer flexibility when you need to make adjustments. Aftermarket control arms are also usually inexpensive. They fit most budgets when it comes to replacements.

Control Arm FAQs

Q1. Are the wishbones and control arms in a car the same component?

A. There’s no distinct difference, and the two terms are used interchangeably. Wishbones derive their name from the triangular shape, which resembles that of a particular bone in birds. They’re control arms in the sense that they articulate and pivot wheels and suspension system of a vehicle. So the simple answer is yes, they are.

Q2. How long do automotive control arms last?

A. About 90 000 to 100 000 miles. The lifespan can be shorter or longer than that depending on how you drive, vehicle maintenance measures, and driving conditions. If it’s a replacement arm, its quality and material will also determine the useful service life.

Q3. What causes control arm failure?

A. Many different situations and happenings can cause a control arm in your car to go bad. The main ones include:

• Unorthodox driving. These include sudden takeoffs, sudden accelerations, and hard braking. Moving parts end up experiencing rapid wear. The sudden forces can take a toll on the control arm components, including its frame.
• Wet conditions. Water causes the parts of a control arm to wear and corrode. The ball joint may have its dust boot break down and the bearing to wear out too soon. Water also causes bushing problems. Depending on the material used to make the arm, excessive moisture results in rusted parts.
• Uneven roads. Rough terrain will cause early damage to the control arms on your car. The component is designed to stand up to damage. However, excessively rough conditions can cause the arm to bend or even break. While some road situations are unavoidable, gentle driving would save the control arms.

Q4. What signs show you have bad control arms?

A. You have worn or damaged arms on your car if you experience these symptoms.

• Excessive steering wheel and chassis vibrations, especially when you accelerate.
• Strange sounds that become more pronounced on uneven roads. Bad control arm noise can range from clunks to snapping or popping and creaking sounds)
• Steering wandering from side to side and causing car control issues
• Uncomfortably feeling every bump on the road
• Uneven tire wear
• A steering wheel that keeps pulling to one side
• Wobbly wheels that may also vibrate when accelerating
• Wheels wearing unevenly

Other symptoms of bad control arms include a car that leans too much when turning and erratic performance of the brakes. You may also have a rear that makes a sudden movement when the car takes off.

Q5. Is it risky to drive with a bad control arm?

A. The simple answer is yes if the damage is severe and no if we are talking about normal wear and tear. Some forms of damage, such as worn control arm bushings, can only cause sounds and uncomfortable rides. A slightly worn ball joint, too.

Dangerous problems include bent control arms, broken frames, or severe cracks. Driving with a broken control arm can be one of the riskiest ventures that you can choose. Doing so could see your car failing to steer properly or developing an unsafe wheel wobble.

Q6. Can you repair a failing control arm?

A. You can. Bad control arm bushings and ball joints can be replaced, especially if the rest of the arm assembly is intact. However, it’s often recommended to change the entire arm if it has damaged parts. That’s because changing the bushings or ball joint is a lot of work as well as costly. You will also still need to replace the other arm eventually.

Q7. Do you need to replace both control arms?

A. If your vehicle uses a double wishbone suspension, the straight answer is yes. You need to change both the upper control arm and the lower control arm. It ensures uniformity, plus the two components have certainly been subjected to the same level of damage. In addition to replacing the arms on one side, also change those on the other side.

Q8. What is the average cost to buy new control arms?

A. Control arm prices range widely depending on the brand, quality, material, and type. The average amount is often around $40 to $100. Different arms are used on different vehicles. The type and model of your car will, therefore, determine the overall cost. Your preference, too. Aftermarket control arms are generally inexpensive when compared to OEM models, for example.

Q9. How much is the control arm replacement cost?

A. Replacing control arms will cost you around $100 to $300. It depends on your type of car and the type of control arm to be installed. The amount will also vary from one area to another and depend on the local auto repair rates. Some car owners choose to go the DIY way and only spend a few dollars to purchase the component.

Q10. What should you look for when buying control arms?

A. Control arms are crucial to safe driving. You, therefore, need to quality ones installed in your vehicle. The correct type, too, for the required performance. Always consider these factors.

Material. Control arm material determines the component’s performance and lifespan. Steel makes strong and low-cost arms but cannot resist rusting. It’s also heavy. Cast iron is robust and lighter, plus it works in a wide range of conditions.

Aluminum is lightweight, sturdy, and does not rust. However, it’s more prone to damage due to its soft nature that causes rapid wear. The inability to bend, too, which causes aluminum control arms to fail by cracking or breaking.

Design. You can buy a press-in, bolt-in, or unitized arm. A built-in ball joint makes replacement tasks easy, especially is considering a DIY control arm installation. However, expect the subsequent replacement to be costly since you have to change the entire arm. Generally, the design that you choose will depend on your car’s suspension type and geometry.

Other important considerations include brand, price, and warranty. Some brands are more quality than others. The one you choose will depend on how well you research the company’s uniqueness in the market.

Prices can indicate a value for quality or a rip-off. A warranty, on the other hand, cushions you in the event of early damage. A long warranty often means the manufacturer is confident that their control arms are quality and longlasting.

Conclusion

The control arms in a car or truck are one of the most simple-looking components. However, their function is among the most important. They hold the wheels to the ground while also allowing them to turn. But that also means undergoing a lot of beating to keep the suspension and steering system functional. Choosing the right control arm for your vehicle is, therefore, essential.