A control arm is a bar that has a pivot at both ends. Your car has several, including the upper control arm and the lower control arm, which are arranged to form the letter A.
Control arms are part of the suspension system. They attach suspension members to the chassis and manage the motion of the wheels so that it synchronizes with that of the body of the car. They work with bushings, which are cylindrical linings that reduce friction and restrain the auto parts from going every which way.
As a result, you are able to go on joy rides without feeling sick and dizzy, as there is control and smoothness in the movement of the car. The two bottom points of the control arms that form the letter A are attached to the frame of the vehicle while the top point is attached to the spindle. Three or four control arms are placed between the rear axle housing and the frame if you have coil springs in both the front and rear suspensions.
Like other body parts, the control arms should also be lubricated at every oil inspection. Handling and steering could become erratic if the control arms are malfunctioning and the unsteady movements of your car could take away your riding comfort.
Control Arm Buyer's Guide
- A control arm is a metal component that’s part of the suspension system that connects the wheel hub to the frame.
- Parts of a control arm include the metal body, bushings, and the ball joint
- A failing control arm could be due to a faulty ball joint, cracked bushings, or a bent metal arm.
- It costs around $20 to $2,300.
In able to help with the up and down movements of the wheel, car manufacturers attached the wheel hub and suspension upright to a control arm. The layout of the wheel assembly depends on what kind of car you are driving. Front-wheel cars usually feature one lower control arm per wheel, while trucks often utilize a two-control arm setup. If your car has one lower control arm, it’s likely because it has a strut-type suspension, as opposed to having an upper and lower arm which indicates a double wishbone suspension.
What is a control arm and why is it a key suspension component?
The control arm is a metal connector that links the wheel hub to the frame. This crucial component is part of the car’s suspension system that guides the wheel as it moves upward and downward. The inner end of the control arm attaches to the vehicle’s chassis and serves as the pivot point of the arm whenever the wheel moves up and down. The outer end, on the other hand, connects to the steering knuckle. Without the control arm, there’s nothing to support the wheel movement and suspension system.
Parts of a control arm
There’s nothing complex about the structure of the control arm. It features a simple mechanism that consists of three parts. Yet, despite its architectural simplicity, control arms are considered to be an engineering ingenuity due to its function. That said, here are the parts comprising a control arm.
The metal arm is both the skeleton and body of a control arm. It comes in varying shapes and designs but the most common of all back in the days is the A-shaped design, which made some people call it the A-arm. Modern control arms nowadays exhibit unconventional designs as products of extensive research and developments, especially in performance vehicles.
On the inner end of the control arm, you’ll find a set of rubber bushings. These bushings are there to prevent metal-to-metal rubbing as the arm pivots in conjunction with the wheel. The bushings also keep the cabin from vibrations caused by uneven road surfaces.
The ball joint is found on the outer end of the control arm, which connects to the steering knuckle. Located below the coil sprin, the ball joint makes wheel turning possible.
Indications of faulty control arms
There are three main reasons why you need to replace your car’s control arm. If you notice strange movements on your wheel, act responsibly by consulting your mechanic. If he or she finds out that the issue is caused by a damage control arm, the only best thing to do is have them replaced because damaged control arms make your vehicle unsafe to drive.
Faulty ball joint
The ball joint is integrated to the control arm and typically comes with it as default. A failing ball joint is easy to miss; your car might have it without you even noticing. However, the consequences of this can be catastrophic, as your car might end up losing control after hitting a bump. The most possible way of detecting a defect on the ball joint is through a thorough check-up by an experienced mechanic.
Cracked and damaged bushings
The bushings play a vital part in the pivoting movement of the control arm, as it prevents the metal connection points of the frame and the arm from rubbing on one another. It also negates the noise from metal-to-metal contact, as much as it absorbs vibration on rough roads. When control arm bushings start to fall apart, the connection point could become loose and the up and down movements of the wheel will be compromised.
Bending on the metal as result of impact hits
The clearest indication of all three is a bent control arm. Control arms are made of steel but that does not guarantee lifetime durability. Keep in mind that your car’s overall weight is distributed to the suspension system. Hitting bumps or being involved in a frontal collision can bend the steel. A vehicle with one or two bent control arm poses a high risk, even a threat, on the road so be responsible and have them replaced as soon as possible.
How much is a control arm?
The price of a control arm depends on what kind of replacement you are after. There are two kinds of replacement control arms, which are OE and performance replacements. OE replacement parts are the ones designed to readily fit your car, while performance replacement control arms are meant to offer additional rigidity and are meant for more intense driving. OE replacement control arms are priced roughly around $20 to $2,100, while performance replacements are at around $160 to $2,300. The parts come as an individual piece, in kits, and sets.
Important Facts You Need to Know About Control Arm
No one wants to have a bumpy ride/ Improve your vehicle's steering control and ensure your wheels smooth movement by getting the right control arm.
If you remember your childhood cartoons, Fred Finstone drove a car powered by his own feet. That's really funny to look at but in our world today, it isn't possible at all. Not only would you get blisters, but you wouldn't be able to steer your ride smoothly as well. If you're after a smooth ride and an easier time steering your car, you have to be sure you're using a quality control arm.
A control arm isn't a piece of robotic machinery you'd find in a science-fiction film. It's actually a strut made of high-quality metal. This suspension part is located the bottom and top parts of your front wheel's spindle and consists of an upper and lower control arm. These lower and upper control arms permit your car's front wheels to change direction without any resistance.
Without the function of this suspension part, you won't have a smooth ride at all. You're going to experience a bumpier ride. There's also a tendency to oversteer or understeer your car whenever you're driving it. If this is what you're avoiding, better have your suspension system checked by a mechanic right away. That way, you'll be avoiding any problems with your car and its suspension system in the future. And if you do need a replacement, better get one right away. Replacement and aftermarket parts are widely available in the market. You can go to your local dealer, or for more convenience, you can always shop for parts online.
Control Arm: Just the Facts
Your vehicle's suspension system is not just about shocks and springs. These components are important, but there are other equally vital suspension parts that complete the suspension system. Among them is the control arm, a triangular-shaped metal strut that attaches the wheel to the vehicle's frame. Aside from providing support for your vehicle's wheels, though, the control arm also performs a more integral role. The control arm allows the front wheels to change directions whenever you make a turn. Hence, this suspension part really is something you can't drive properly without. There are basically three or four control arms in your vehicle, each unit carrying driving and brake torque. Because of its load-bearing and supportive functions, though, the control arm also commonly experiences early wear and tear. But relax, CarParts.com has the best replacement control arm for your vehicle.
• Manages the wheels' motion in relation to the vehicle's body
• Reliably connects suspension parts to the chassis
• Easy part installation guaranteed
Control Arm: What Every Car Owner Should Know
All parts of a car, whatever the car's make or model, are susceptible to wear and tear. Especially vulnerable are the suspension parts, like the control arms. You're going to need a control arm kit to replace these arms once they're worn out.The control arms hold and allow the steering knuckle to move vertically, to follow the shape of the road. Each side of an arm has bearings bolted onto the frame or body, and steering knuckle. The ball joint bolted to the steering knuckle is especially susceptible to wear and tear and is a common cause of steering issues.One quick method of testing the ball joints is to hold one with your fingers and wiggle it about. If it offers little to zero resistance, then you definitely need a control arm kit. Otherwise, your car's steering is going to get even worse.Each kit should include control arms and all the necessary mounting hardware. They're available here at Carparts.com.
• Our control arm kits restore the functions of your car's suspension system.
• Control arm kits from us come complete with the needed rods and hardware.
• You can get kits for driver and passenger-side applications.
A Beginner's Guide to Installing a Control Arm
Whether you're replacing a faulty control arm or just switching to a high-end performance arm, installing a new control arm in your car requires a bit of patience, skill, and the right tools. In this installation guide, we'll show you how to properly install a control arm on your car.
Required skill level: Intermediate
Needed tools and materials
- Ball joint separator and press
- Ballpeen hammer
- Pry bar
- Tire iron or breaker bar
- Torque wrench
Prepping the car
Park your car on a solid level surface and apply the parking brake. Using either a tire iron or a breaker bar, loosen the lug nuts on the wheels but do not remove them. Next, use a floor jack to lift the vehicle and place jack stands underneath both sides of the car. Preferably the jack stands should be placed on the pinch welds and the frame, but if your car has a coil spring with SLA suspension, place one of the stands close to the ball joint.
Removing the parts
Once the car is secure, remove the lug nuts and the wheels. Take out the cotter pin and pinch bolt from the ball joint and separate the ball joint from the knuckle with a ball joint separator. Remove the ball joint nut, steering knuckle and other components still connected to the lower control arm. Once they're removed, detach the control arm mounting bolts and control arm itself.
Installing the new parts
Press the ball joint in place on the new control arm with a ball joint press. Slip in the control arm with the attached ball joint to its mounting. Line up and start all the bolts but don't tighten them - this is in case the bolts don't line up correctly on the first try. Install the steering knuckle, cotter pin, and other components of the control arm back to their respective places.
Reinstall the front wheels and lug nuts and lower the car to the ground. Once the vehicle is at a normal riding height, torque the lug nuts and control arm mounting bolts according to their proper torque.
Control Arm Options: Getting the Right Component for Your Vehicle's Suspension
If you enjoy smooth rides and accurate steering control when you drive, a sturdy, hardworking control arm has much to do with this, along with other suspension parts. This arm keeps the wheels moving in sync with the auto body, making the vehicle handle pretty well. Due to the stress, however, it may be damaged or can become weak over time. The bushings attached to it may wear out, causing the suspension to make noise. A faulty suspension arm may result in loss of precision and poor handling. To bring back the good performance of your suspension, you’ll have to get rid of the busted arm and put in a new one.
When in the market for a new control arm, you have to:
- Know the type of suspension system used in your vehicle and the suspension arm design that will match the specs and requirements of your vehicle.
- Search for a high-quality replacement. It has to be made from high-grade materials and has to be tested to meet industry standards.
- Shop around and compare for the best prices. The price range varies according to the type of suspension system, arm design and features, brand, and seller.
Types of suspension system
There are basically two types of suspension system that use control arms.
Double wishbone suspension. A-shaped control arms are used in this suspension system.
Macpherson strut suspension. Only one control arm is used in this kind of suspension—instead of an upper arm, a vertical telescopic strut that’s linked to a coil spring is used.
Compared to the double wishbone suspension, the Macpherson strut has a more restricted vertical movement. It is less complex, and in terms of cost, it’s less expensive. Double wishbone suspension, on the other hand, is quieter but also more complicated. It allows vertical movement. Small, compact vehicles are typically equipped with Macpherson struts, while double wishbone suspension is more commonly used in larger, more luxurious vehicles, although MBs, BMWs, and Porsches may sometimes be designed with Macpherson strut suspension.
Control arm design
Unitized. This arm has a built-in bolt joint. It comes in a single unit and not a separate piece. So when the arm or ball wears out, the whole unit is replaced.
Press in. This kind is used in wide-range applications, though this seems more fitting for heavier vehicles such as trucks, vans, and SUVs. This arm design uses a bigger ball joint.
Bolt In. This design is used in Macpherson strut suspension. It comes with a stamped strut-type arm body.
Replacing Your Vehicle's Old Control Arm
The control arm may break or fail due to damaged bushings or ball joints, wear from suspension stress and from impact, or distortion because of improper towing. Whatever the reason is, a faulty arm will always lead to poor vehicle handling, loss of control, and lack of precision. A little bit of detective work will confirm if the old arm has to go. If it’s time to replace it, here are the steps to help you with some DIY:
Note: This installation guide isn’t applicable to all makes and models. You have to read the vehicle manual for further instructions and other important details about the control arm of your vehicle.
Difficulty level: Moderate
Tools you’ll need:
- Ball joint separator
- Pry bar
- Ball peen hammer
- Torque wrench
- Tire iron or breaker bar
- Floor jack
- Jack stands
Step 1: Park the vehicle on a level ground and use the parking brakes.
Step 2: Break loose the lug nuts on the front wheel using a tire iron or breaker bar. Don’t remove them just yet.
Step 3: Jack up the vehicle’s front section and place some jack stands on each side.
Step 4: Undo the lug nuts to remove the front wheels.
Step 5: For vehicles with short/long arm suspension and coil spring, a floor jack (sitting near the ball joint) must be used for supporting the lower control arm. Before you remove the lower arm, it’s important for the coil spring to be contained. For vehicles with torsion bar suspension, you have to remove the tension on the bar.
Step 6: Detach the cotter pin from the ball joint nut, if it comes with one. You have to loosen this nut. However, you shouldn’t remove it yet. Next thing you have to do is check the ball joint. If it comes with a pinch bolt, unscrew this bolt.
Step 7: Use a ball joint separator for detaching the ball joint from the knuckle. As you remove the nut, keep the knuckle out of the way.
Step 8: Disconnect components that are linked or attached to the lower arm.
Step 9: Pull out the assembly after removing the mounting bolts.
Step 10: Fit in the new arm and secure it with the bolts. Adjust the vehicle to proper riding height before the bolts are torqued.
Step 11: Put back the steering knuckle to the assembly.
Step 12: Put in the castle nut and torque it according to manufacturer specifications. Use a new cotter pin and reconnect components previously attached to the arm.
Step 13: Place back the front wheels and secure them with the lug nuts. After bringing the vehicle to the ground, you have to torque the lug nuts and control arm mounting bolts according to specs.