You Should Know This About Control Arms
The smooth and comfortable ride you have come to expect from your vehicle is only possible because of the control arms. A control arm assembly plays a vital role in the suspension and steering system of the vehicle allowing the wheels to be suspended from the vehicle for better control and stability. Ensuring the control arms are in pristine condition is going to provide a safer and more comfortable drive. Here we look at all the important aspects of buying new control arms so that you get the best match for your vehicle.
1. What Are Control Arms and What Do they Do?
- What Does a Control Arm Look Like?
- What are the Two Types of Control Arms?
- What Does Lower Control Arm Do?
2. What Should I Consider Before Buying Controls Arms?
- Compatibility
- Control Arm Material
- Corrosion Resistance Coatings
- OE Vs Aftermarket Part
- Individual Control Arm Or Full Kits
- Brand Choice Considerations
3. What Are The Types Of Control Arms I Should Be Aware Of?
4. What Top-Quality Brands Of Control Arm Shall I Choose?
- Moog Control Arms
- Mevotech Control Arms
- Delphi Control Arms
- Transit Warehouse Control Arms
- Dorman Control Arms
5. What Are The Symptoms Of Bad Controls Arms?
6. How to Move a Car with a Broken Control Arm?
1 What Are Control Arms and What Do they Do?
Control arms are structural suspension system components that connect the vehicle’s chassis with the wheels. The control arm connects to the chassis with bolts that run through bushings. This connection acts as a hinge allowing the control arm to move vertically or horizontally depending on the orientation of the bushing. This hinged movement is important as it allows the wheels to move independently of the chassis which improves ride comfort and handling performance.
The other end of the control arm is attached to the wheel hub with either bolts or ball joints depending on the suspension type and location of the control arm. The ball joints help with suspension articulation to maintain wheel contact with the ground as the vehicle goes over road imperfections and in the case of the front wheels, these ball joints allow the spindle to rotate freely.
The number of control arms and the type can vary based on the suspension type and location of the arm. Independent suspension systems utilize one or more control arms according to the design. Most vehicles have front control arms but only a few have rear ones. The most common types of front suspension include Double Wishbone and Macpherson Strut. Control arms can be either an ‘A’ or ‘L’ shape or a simple shaft.
The main function of control arms is to isolate the wheel movement from the chassis which does two things – Firstly it helps dampen vibrations from the wheels, providing smooth and plush ride quality, and secondly, it maintains constant wheel contact with the ground for better steering and control over the vehicle. This is the reason why broken control arms can compromise vehicles’ safety and put the driver and passengers at serious risk.
What Does a Control Arm Look Like?
Control arms can come in many different shapes and sizes, but most commonly, they are shaped like a capital letter “A”. The two lower parts of the “A” are attached to the frame via control arm bushings, which are rubber pivot-points. The top of the “A” is attached to the steering knuckle by way of a ball joint.
What are the Two Types of Control Arms?
The most common types of control arm suspensions are:
- Control arm type suspension
- Strut type suspension
In a control arm type suspension, the control arm is a separate component from the shock absorber. The control arm is connected to the frame of the car and the steering knuckle by ball joints. The shock absorber is mounted separately.
In a strut type suspension, the strut becomes the upper control arm and is sometimes connected directly to the spindle or the lower control arm. Strut type designs have a lower control arm but no upper control arm.
What Does Lower Control Arm Do?
The lower control arm is a component of the suspension system in a car that helps maintain contact between the wheels and the road surface. It is a link that connects the frame of the car to the wheel hub assembly or steering knuckle. The control arm moves up and down with the spring when a car hits a bump or other road irregularity, allowing the tires to maintain contact with the road and, thus, control. The two lower parts of the “A” are attached to the frame via control arm bushings, which are rubber pivot-points. The top of the “A” is attached to the steering knuckle by way of a ball joint. When a control arm fails, multiple things can happen. Most failures occur from the ball joint failing. Complete ball joint failure can cause a steering knuckle disconnection and loss of control of the vehicle. Control arm bushings can also wear and fail, creating clunking, wandering steering, and loss of control.
Our Top Picks For Control Arms
2 What Should I Consider Before Buying Controls Arms?
Compatibility
The suspension system of almost all vehicles is different from one another and this difference may even exist between different models of a particular make or even versions of the same car. This makes it necessary to choose control arms specific to your vehicle’s make, model, and year of manufacture. Normally you can find it very difficult to find exact matching parts for your car in the aftermarket but PartsAvatar makes it easy for you. Select your car’s exact model, make and year to get products that are direct OE replacements. This removes the guesswork when buying new parts.
Control Arm Material
As mentioned earlier, control arms are mainly built with three materials – iron, aluminium and steel. Aluminium control arms are lighter than other types which translate to reduced unsprung mass and lighter weight on the vehicle. Such arms can absorb noise and vibrations better due to the density of the material. Another advantage is their corrosion resistance making which allows them to be used in varied weather conditions. Therefore aluminium is ideal for performance and luxury vehicles as they provide enhanced comfort and handling properties or in places where the weather is mostly wet.
Steel control arms are more affordable than aluminium and generally have a long service life unless exposed to constant wet conditions. These types of control arms are sufficient for most compact cars and sedans that do not face harsh driving conditions.
Cast and forged iron control arms are sturdier than steel and can withstand heavier loads which is necessary for heavy-duty applications like trucks and pickups. They can even be lighter than steel arms for reduced unsprung weight.
Corrosion Resistance Coatings
One of the most common reasons for control arm failure is corrosion. Due to their location, the control arms are always exposed to the road and weather conditions making them vulnerable to rust which can significantly reduce their service life and will require more frequent replacements. To combat this, many manufacturers apply protective coatings on steel and iron control arms to prevent corrosion and extend component life. When buying steel or iron control arms it is necessary to look for resistance coatings that ensure the components will last a long time and provide a healthy service life. Such treatments are usually showcased by the manufacturer so look for the information before buying new control arms.
OE Vs Aftermarket Part
Replacement OE components offer the same advantages as the factory-equipped parts and nothing more. This means you will not receive any additional benefits. These will also cost quite a bit more than aftermarket parts. Whereas aftermarket components are generally cheaper and come at a reasonable price while providing many benefits over standard control arms. Aftermarket components match the fit and performance of the OE parts and some even exceed that. Hence making them a bargain over OE counterparts.
Individual Control Arm Or Full Kits
Control arms are available as a single unit or complete control arm kits. While a full kit is recommended, if replacing just a damaged section then a single control arm is more feasible. Usually, it is best to replace both fronts – right and left, or both rear control arms together including the upper and lower arms if your vehicle has both.
Opting for a full control arm kit will ensure you don’t have to worry about replacement any time soon. Since the control arm replacement can be expensive, it is generally more economical in the long run to go for a complete replacement to minimize labor costs. Full kits also come with all the required fasteners and parts, which reduces cost and saves time during installation.
Brand Choice Considerations
Different brands offer different advantages and benefits. These features need to be considered when buying new control arms. Some aim at making the components durable, while others offer easy installation procedures. To get control arms best suited for your needs, consider the technologies used to manufacture them. Corrosion treatments and powder coatings on control arms resist corrosion and last for a long time. Another thing to consider is the warranty offered. If a company offers a lengthy warranty for their control arms, it can mean that they are confident about its quality. So the features mentioned along with the various brands can help you match the one best suited to your needs. The brands mentioned here are a few of the best manufacturers in the market producing OE equivalent components at a much more reasonable price which is why we recommended those brands.
3 What Are The Types Of Control Arms I Should Be Aware Of?
The control arm design and construction can vary depending on a few factors such as suspension and vehicle type and the location of the arms. The types of control arms are as follows:
Based On Adjustability
There are adjustable and non-adjustable control arms. Adjustable ones can alter the alignment of the wheels. Such control arms have threaded sleeves that travel inwards or outwards to push or pull the wheel which changes the camber angle.
Based On Materials Choice
Since control arms are structural components they need to be made of robust materials that can withstand heavy loads, stresses, and pressures. This means the material choice needs to meet high standards as well as the manufacturing processes to ensure safe, reliable, and long-lasting service life. The materials used for control arms include steel, aluminum, and iron. Steel control arms are the most widely used type due to their strong construction and inexpensive manufacturing. Steel control arms are often used as OE by manufacturers as they are cheaper to mass-produce and have high strength characteristics. The drawbacks to steel control arms are their heavier weight and susceptibility to rust. Cast and forged iron arms are similar to steel counterparts in strength but weigh less and can withstand much heavier loads and varied weather conditions making them ideal for trucks and heavy-duty vehicles. However, these are also susceptible to rust.
Aluminum control arms have many advantages over steel and iron alternatives, most importantly they are not prone to corrosion. They are also much lighter than steel which is favorable if you want better driving and handling dynamics from your vehicle. Suspension components contribute to the un-sprung mass so the lighter the components the better the vehicle will tackle a turn. A reduction in overall vehicle weight is also an added advantage. Well-made aluminum control arms can match and even exceed the strength of steel arms. The only drawback is that aluminum does not flex under stress, unlike steel, which can result in cracking or breaking under heavy-load conditions or upon impact.
Based On Function
Control arms can be classified as supporting and guiding types based on their functionality. Supporting type control arms are load-bearing and support the weight of the vehicle. Whereas guiding control arms help distribute various forces like braking and acceleration to the wheels evenly. They are not loaded but provide structural rigidity to the suspension and wheel assembly.
Based On Design
The control arm design mainly varies based on how the ball joint is attached to the arm. There are three variations – bolt-on, press-in, and unitized control arms. Bolt-on type control arms have an indentation and holes where the ball joint bolts onto the control arm. This allows the ball joints to be replaced independently of the control arm and vice-versa. These are generally made of stamped steel. Similarly, press-in type arms have ball joints that are integrated into the control arm but without the use of bolts. Instead, the ball joints are pressed into a receptacle in the control arm that accepts the joint. Such control arms are made with forged arms for sturdier working and so are commonly used on heavy-duty vehicles.
Unitized control arm assembly incorporates ball joints into the arm with the ball joint built into it. This means the ball joint or control arm alone cannot be replaced and the control arm assembly needs to be replaced entirely. Unitized control arms are becoming increasingly popular due to lower production costs and are commonly made with aluminum.
4 What Top-Quality Brands Of Control Arm Shall I Choose?
Moog Control Arms
Control arms are a critical safety component-to ride right, to handle right, and to ensure safety and dependability they need to be engineered and built right. Moog makes thousands of control arms for the broadest range of applications. And while no two applications are the same, every Moog control arm is engineered and manufactured with the same goal in mind-to ensure durability, reliability, and performance.
Moog Premium Control Arm Part Numbers: CK80398, CK80306, CK80397, CK620054, CK80669, and more.
Premium Control Arms Features:
- Problem Solver® Gusher Bearing: Metal-to-metal design provides strength and allows grease to flow through the bearing surface for reduced friction and long life
- Greaseable Socket: Reduces corrosion and wear by allowing new lubricant to flush contaminants
- Keeps Dirt And Water Out: Pre-installed dust boot shields socket components from wear-causing contaminants
- Absorbs Impact: Belleville preload washer helps keep the bearing package tight as bearings wear
- Quiet Operation: Premium pre-installed bushings with optimized stiffness inhibit noise for a more comfortable ride
Moog R-Series Control Arm Part Numbers: RK640734, RK641845, RK620111, RK641338, RK80411, and more.
Moog R-Series Control Arm Features:
- Easy To Install: Precision tolerances for easy installation and steering alignment give you a perfect fit right out of the box
- Highly Precise Engineering: Optimized bushings for quiet operation and resistance to wear, salt, road grime, and oils
- Comprehensive Coverage: Available for foreign and domestic nameplates
- Long Life: Ball stud shape ensures fatigue life, compensating for sag and suspension and adding extra swing when you need it
- Enhanced Structural Strength: Heat treated to match or exceed OE requirements to inhibit premature failure
- Added Corrosion Protection: Coated studs and e-coated cast iron and steel control arms inhibit premature deterioration.
For more information and a detailed product line, visit Moog Control Arm Section.
Mevotech Control Arms
Mevotech gives technicians the edge, by innovating every control arm component. On average, installing their control arms takes 30% less time because the ball joints and bushings are pre-installed. Mevotech engineers focus on making the components easier to install and built to provide a long-lasting service life. Employing rigorous durability testing, they validate every new design to ensure you get the performance you can trust.
Mevotech Control Arm Part Numbers: CMK80399, CMK80306, CMS40112, CMS30195, CMK80308, and more.
Features:
- Stamped Steel construction meets or exceeds OE specifications.
- Corrosion-resistant surface treatment prevents the build-up of rust for longer service life.
- X-factor Durability: Manufactured with Mevotech patented sintered metal bearings for superior durability and service life
- Overbuilt with sintered metal-to-metal technology for added endurance and durability
- Built with thicker material for increased strength
- SAE grease fitting is included for serviceability
- Added labor saver feature saves you time and money with bundled hardware
- Corrosion-resistant surface treatment prevents the build-up of rust for longer service life
- Forged steel control arm with a filled-in hole/recess & thicker cross-section for additional stiffness and strength
- Enhanced bushing design using upgraded rubber, with added knurling which locks the control arm bushing to the sub-frame.
For more information and a detailed product line, visit Mevotech Control Arm Section.
Delphi Control Arms
Delphi Technologies Chassis products are manufactured to meet the exact same tensile strength, flexibility, and longevity as the original equipment. They test their products alongside the OE part for 250,000 cycles to check braking force, cornering force, and suspension travel movement, so you can be certain the part will perform like the OE.
Delphi Control Arm Part Number: TC1450, TC1449, TC2874, TC2468, TC2467, and more.
Features:
- Extensive dimensional and material analysis to ensure the very best compatibility between the OE and aftermarket parts.
- Parts exposed to 720 hours of salt spray for optimum protection against corrosion.
- Additional cataphoretic coating for greater protection against corrosion and enhanced aesthetics.
- Delphi control arms undergo 100% crack detection and ultrasonic flaw detection tests to ensure materials match OE specifications.
- Robot welded for consistent performance and quality.
- Anti-corrosion protection is applied to each part.
- They test their parts to the extreme, from every angle, for reliable performance at temperatures below -40°F and over 248°F.
- Suspension kits designed for simple, complete steering repairs
For more information and a detailed product line, visit Delphi Control Arm Section.
Transit Warehouse Control Arms
TOR offers a full range of heavy-duty steering and suspension car parts, built for optimal fit and extended service life. Each component is tested throughout the manufacturing process to ensure exceptional performance and reliability.
Transit Warehouse Control Arm Part Numbers: TOR-CK621453, 72-CK620040, TOR-CK622159, 72-CK80397, TOR-CK80306, and more.
Features:
- Premium quality precision-machined components built to last
- Engineered to withstand extreme weather conditions
- Delivers a smooth, stable ride
- Follows punishing testing processes
- Multi-Axis Vibration: to confirm overall design durability
- Impact Resistance: to verify the material’s toughness
- Salt Fogging: to check surface coating corrosion resistance capabilities
- Artificial Ageing: to ensure long-term durability and safety
For more information and a detailed product line, visit Transit Warehouse Control Arm Section.
Dorman Control Arms
Dorman suspension control arm and ball joint assemblies are a direct replacement for the original equipment on wide-ranging vehicle applications. An industry-leading evaluation process ensures directional stability, a smooth ride, and favorable dynamics.
Dorman Control Arm Part Numbers: 520-494, 520-493, 520-866, 524-113, 521-108, 526-289, 521-637, 524-102, 520-283, 520-284, 522-467, and more.
Features:
- Trustworthy Replacement: This control arm and ball joint assembly directly replaces the original assembly on specific vehicle applications
- Complete Repair: Each assembly includes pre-installed ball joint and bushings, saving time and labor
- Quality Engineering: Underwent industry-leading testing to ensure a smooth, stable, and safe ride
- Durably Designed: Additional coatings offer long-lasting rust and corrosion resistance.
For more information and a detailed product line, visit Dorman Control Arm Section.
5 What Are The Symptoms Of Bad Controls Arms?
No matter what material the control arm is built with or how well it is built, it is vulnerable to wear and tear especially because it undergoes immense stresses and forces regularly which can eventually cause the component to fail. The signs of control arm wear become more obvious as it deteriorates and so it is important to look out for these signs to scope out the issue beforehand and replace it to minimize damage.
Vibrations
The most common failure point of control arms is the bushings. Since these are used to minimize vibrations, worn control arm bushings can induce vibrations in the wheel that can even travel all the way to the steering wheel. Failing ball joints can also cause vibrations. An uncomfortable rive is an early sign of something going wrong with the suspension components.
Vehicle Pulling To One Side
Worn bushings and ball joints upset the alignment of the wheels which can cause the vehicle to steer from left to right involuntarily. This will cause the driver to lose control over the vehicle and can be seriously dangerous when traveling at high speeds.
Clunking Noises
When the bushings wear out, the metal components directly contact each other which gives rise to clunking and knocking noises. These sounds are more prominent as you accelerate and brake. Ball joints show a similar symptom when they fail as the play within the joint increases, the control arm becomes loose and noises increase. These sounds are faint at first but if ignored, the noise intensifies and so does the problem.
Uneven Tire Wear
There are several reasons for uneven tire wear which include bad control arms. Since control arms are integral suspension components, wear and tear of the components causes the wheel alignment to be changed which modifies the wheel contact patch and results in uneven tire wear. The inner or outer tire shoulders may wear more than the other end indicating uneven tire wear. Inspect your vehicle immediately to mitigate the problem and find a solution.
| Moog Control Arm – Part Number Catalog | |
| Category | Part Numbers |
| Premium Control Arms | CK80398, CK80306, CK80397, CK620054, CK80669, CK620258, CK80942, CK620065, CK7424, CK620006, CK620066, CK8728T |
| R-Series Control Arms | RK640734, RK641845, RK620111, RK641338, RK80411, RK642799, RK641594, RK642800, RK641242, RK620566, RK80669, RK8030 |
| Mevotech Control Arm – Part Number Catalog | |
| Category | Part Numbers |
| Control Arm Assembly | CMK80399, CMK80306, CMS40112, CMS30195, CMK80308, CMS25189, CMS30180, CMS901104, CMS401101, CMS30146, CMS76179, CMS501118 |
| Delphi Control Arm – Part Number Catalog | |
| Category | Part Numbers |
| Control Arm Assembly | TC1450, TC1449, TC2874, TC2468, TC2467, TC2345, TC1007, TC882, TC1075, TC2402, TC3293, TC2394, TC1310 |
| Transit Warehouse Control Arm – Part Number Catalog | |
| Category | Part Numbers |
| Control Arm Assembly | TOR-CK621453, 72-CK620040, TOR-CK622159, 72-CK80397, TOR-CK80306, TOR-CK620374, TOR-CK80669, 72 CK62004, 72-CK80398, 72-CK620066, TOR-CK620577, TOR-CK620505, 72-CK80670 |
6 How to Move a Car with a Broken Control Arm?
If your car has a broken control arm, it is not safe to drive. If you must move the car, it is best to have it towed to a repair shop. Driving with a broken control arm can cause a steering knuckle disconnection and loss of control of the vehicle. If you’re unsure about how to proceed, it’s best to have your control arm replaced by a professional. You may find it simple to replace a front lower control arm on a vehicle with a MacPherson strut suspension. But if you’ve got a torsion bar suspension, you’ll need a lot of mechanical knowledge in order to complete this job.
