Aug. 25, 2025
The term ‘control arm’ doesn’t find its way into the discussion about vehicle parts all too often, leaving many people to wonder, ‘what are control arms?’. This post will answer that question and discuss the different types of control arms and their uses.
If you are looking for more details, kindly visit our website.
A control arm, also known as an A-arm (or control link in the railway industry), links the vehicle chassis and suspension hub that carries the wheel. They are the metal components you can see that connect the vehicle body to the wheel assembly in automotive vehicles.
Control arms are a vital component of a vehicle’s suspension system, allowing tyres to move in line with the vehicle’s body. They are made up of three main parts: bushing, body and ball joint. The control arm body connects to the vehicle frame via the bushings (usually rubber bushings) and connects to the wheel side of the vehicle suspension with a ball joint. In combination, these components allow smooth, controlled movement when pivoting, turning and driving on the road, by allowing the wheels to move up and down while remaining in contact with the ground for stability. Control arms also reduce friction and vibration when steering.
Automotive vehicles usually have between two and four control arms, depending on the vehicle suspension. However, most modern cars only have control arms in the front wheel suspension. Larger or heavy-duty vehicles like trucks may have control arms in the rear axle.
Having a correctly working control arm and suspension system keeps your tyres in place when you hit a bump or pothole in the road, which is important for your safety on the road. If your steering wheel is vibrating or feels hard to control, or you experience any loud banging, clunking noises when driving over bumps, this could be a signal that you need to replace your control arm assembly.
Control arms are usually made of either stamped steel, cast iron or cast aluminium; each of which has its advantages and disadvantages.
Stamped steel control arms are primarily used in cars; however, they are susceptible to rust in damp environments and can easily damage. As they’re relatively inexpensive to produce and replace, steel control arms are usually found in cheaper, modern cars.
Cast iron control arms are generally used in modern heavy-duty vehicles, like trucks and SUVs, as this strong material copes better in harsh environments, and is not prone to rust. These types of control arms are usually used in front suspensions. The sturdy nature of cast iron control arms makes them superior for vehicle steering and handling.
Cast aluminium control arms are strong and light mechanisms. While aluminium is more resistant to corrosion, it can be more susceptible to wear upon impact due to the softer nature of this metal.
You will have probably come across control arms in cars, however control arms also aid axle location and resistance to breaking in traction forces in all automotive and rail vehicles. Control links are also used in industrial vehicle suspension systems, for example, off-highway vehicles. Different types of control arms are used for different purposes. Below, we have outlined the two main types of control arms and their applications:
A MacPherson strut suspension is an independent front suspension found in most cars. In the MacPherson strut suspension, there is only a single, lower control arm, at each wheel and the strut becomes the upper control arm, which supports most of the weight. This type of control arm can be found in both front and rear suspensions, but usually at the front. Due to the compact design, low weight and relatively cheap manufacture cost, you generally see a strut type suspension in modern, inexpensive cars.
A double wishbone suspension is a type of control arm mechanism used when two control arms are installed in the suspension system. This type of control arm is usually used in modern vehicles, like sports cars, high-end performance cars and light trucks. This is because double wishbone suspension benefits better handling and control.
Lower control arms are only important if you want to be able to maintain control of your vehicle.
Seriously, however, because this is a potential safety problem, it cries out for a second opinion, preferably from a mechanic who is not affiliated with a chain operation. That means avoiding…Meineke, Monro, Midas, Sears, Pep Boys, Firestone, AAMCO, and others of that ilk.
Goto Zegao Machinery to know more.
I strongly suggest that you take your vehicle to an independent mechanic, and ask him to inspect your front end. If he comes up with a lower control arm issue, then you need to have these components replaced a.s.a.p., before you wind up in a serious MV accident.
I can’t speak to whether you need this repair or not. But if you do, it is needed for your own safety.
Think about it this way. Cars are sort of like bobble head dolls. The wheels aren’t bolted to the body, but instead are connected mostly by wiggly springs. That makes for a better ride. But if it was only springs, the wheels wouldn’t stay in the correct orientation, pointing just in the direction you wanted to go. Instead they’d be wobbling around, pointing every which way. So the car designers came up with some other gadgets to hold the wheels in the correct orientation. They decided the springs were only necessary for up and down movement of the wheel w/respect to the body. For going over bumps. For the other potential wheel-movements, to control the wheels they’d use long arm-shaped metal gadgets called “control arms”. The control arm bolts on one side to the body, and the other side to the wheel suspension parts. There’s plastic or rubber bushings on each side usually too, to allow for a limited amount of movement. So that’s what the control arms are for, and if they aren’t working, you won’t have the required control of the direction your wheels are pointing. Driving on the freeway at 75 mpg, this wouldn’t be a good thing.
What everyone else said.
Get a second opinion from an independently owned and operated shop. And if you do need lower arms and/or bushings, let the independent do them. If the independent cannot verify the need, never go to that Meinike shop again.
Actually, I don’t like chain shops anyway. Many of them have business models that promote dishonesty. Like paying their mechanics commissions on all the work they can “drum up” beyond their quota.
Meinekee and chains/dealers does not stay in business with $19.99-$30 oil changes. They stay there by recommending items that others may seem acceptable and charge considerably for repair.
Ask around for trusty mechanic, they exist however may not have best waiting facility or keep your vehicle longer.
That being said you may need the repair but best to ask for 2nd opinion if repair is expensive and no established relationship.
I typically ask to be shown and find the item is not torn or clunky and say next time…
In a lot of cases these days, the ball joints are not removable from the lower control arms. They must be replaced as a unit. I don’t know if that is true of your vehicle. Even if that IS the case, $ for the pair seems high to me.
On a slightly different, but related, note, I had to replace the ball joints on an '08 Dodge Grand Caravan a while back. They are an example of some that only come with the lower control arms. I priced them at three parts stores, two chains and one mom and pop. I found that they were cheaper by over $40 each at the dealer.
In another case, one of my customers came directly to me after Meineke told him he needed $900 worth of completely unnecessary repairs. To add insult to injury, his supposedly freshly changed oil was still brown and dirty, and the oil filter had mud and rain stains on it. THEY HADN’T EVEN BOTHERED TO CHANGE HIS OIL.
As stated earlier, get a second opinion. Click on the Mechanics Files link at the top of this page to find a good one near you.
Edited after looking at www.rockauto.com: The ball joints for your Sienna are available without the control arms.
The company is the world’s best control arms on a car supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.
Previous: None
If you are interested in sending in a Guest Blogger Submission,welcome to write for us!
All Comments ( 0 )