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If you’re like most folks, the first time you heard of a control arm was when your mechanic informed you that yours may need replacing. And, if you’re like most of us, your reply was likely something along the lines of “what the heck is a control arm?”
That, among others, is the question we’ll seek to answer in this article. Because the fact of the matter is, the control arm is not only something everyone should understand, it’s one of the key components of just about every vehicle on the road.
Let’s get started!
Control arm basics
Control arms have been around, in one form or another, for almost a hundred years, ever since mankind got serious about its automobiles. They are the unsung heroes of your vehicle’s suspension system, and perhaps the single most critical component in that system.
Control arms are heavy metal arms made of either stamped steel, cast iron, or cast aluminum–depending on the vehicle–that serve as primary connection points between your vehicle’s frame, the steering knuckle, and the wheel assembly.
The main function of a control arm is to control the vertical alignment of the wheels. They allow the wheels on the vehicle to move up and down as necessary with the surface of the road, maintaining contact and allowing the driver to retain control of the vehicle on uneven ground.
A vehicle equipped with control arms in its suspension may use either a one or two-arm setup, depending on how the vehicle itself is designed.
Types of control arms
Four basic types of control arms are found in just about every road-going vehicle’s suspension system.
- Lower control arms
Lower control arms, as the name suggests, are attached to the lower side of the wheel assembly. Many cars available to consumers have what is known as a Macpherson Strut, which looks similar to a long metal rod with a spring wrapped around it, as the upper portion of the suspension system.
Vehicles in which the Macpherson strut is used only use the lower control arms in the suspension design, as the Macpherson eliminates the need for an upper control arm.
- Upper control arms
Many trucks or heavier vehicles, especially those designed for off-road use, utilize a two-arm suspension system. In these systems, the upper control arm connects to the topmost part of the wheel assembly.
As a general rule of thumb, two-arm suspension systems are heavier and more robust, allowing for greater stability on uneven patches.
- Trailing arms
Trailing arms are not as ubiquitous as the upper and lower control arms. They are only found on vehicles with ’trailing arm’ suspension systems. If your vehicle has a leaf spring suspension, a multi-link suspension system, or any other kind of suspension system, you will never have to worry about trailing arms.
Trailing arm suspensions, in essence, connect your vehicle’s axis to the chassis. They differ from other types of control arms in that they do not directly link to the wheel assembly, but rather the solid portions of both the front and rear axles.
- Adjustable control arms
Adjustable control arms are a type of specialty control arm that is used almost exclusively in raised or lowered vehicles. Because these vehicles are non-standard, the control arms on them must be adjusted to fit with the new vehicle profile. Unless you have modified your vehicle in some way such as through a lift kit, you will not need to worry about adjustable control arms.
Adjustable control arms allow you to calibrate the angles of your suspensions’s pinions and casters, allowing for precise alignments and centering of the axle, which in turn can improve the vehicle’s performance in uneven ground or off-road situations.
Symptoms of a bad control arm
Because control arms are such an integral part of your vehicle’s suspension, it’s important to be able to identify when one of them might be going bad. Fortunately–or perhaps, unfortunately, depending on your perspective–there are a variety of symptoms that can serve to indicate whether they’re going bad.
Because a control arm is directly attached to both the suspension and the steering systems, you will most likely experience symptoms related to unpredictable steering or an abnormally rough or bouncy ride. These symptoms may include, but are not limited to:
- Vibrating steering wheel
- Loose or wandering steering wheel
- Popping and clunking sounds coming from the front of your vehicle
- Poor wheel alignment or shaky wheels
- Poor shock absorption
- Uneven tire wear
I think I have a bad control arm, now what?
Do I need to replace a bad control arm?
In a word, yes. In two words, most definitely. In three words….you get the point.
A bad control arm means that not only is your vehicle’s suspension compromised–which could lead to the wheel bouncing up and striking the body of the vehicle, or dropping too low and causing the body of the vehicle to impact with the ground–but it also means your steering is compromised as well.
A vehicle with a bad control arm may and eventually will experience uneven and unpredictable steering. You may find your vehicle weaving back and forth as the steering fails, or it may respond in unpredictable ways during turns or other maneuvers. This makes your vehicle not only a danger to yourself, but to every other driver on the road.
If you believe your control arms are beginning to fail, you must get them diagnosed and, if necessary, fixed and replaced as soon as possible.
How much does it cost to replace a control arm?
It depends on your vehicle’s make, model, and year. Likewise, labor costs can also be affected by different factors, but here are some rough estimates.
In general, you can expect to spend between $100 and $500 [CA $137 and $685) on new parts when replacing a failing or damaged control arm system. The price difference is based almost exclusively on the type of vehicle you own. A 2015 Honda Civic will have parts that cost far less than, say, a 2022 BMW.
In general, you will have to replace the arm rather than attempt to repair it, as anything that may cause it to fail enough to be noticeable will also be something that cannot be safely repaired.
In addition to the parts, labor will generally run you anywhere between $150 and $200 [CA $205.50 and $274]. These prices may increase or decrease depending on where you live, and whether or not you take your vehicle to a local mechanic or a dealership.
If you are looking to save some money on repairs, one reliable way is to purchase aftermarket parts from a reliable distributor such as AutoShack. Aftermarket parts are almost always cheaper than buying brand-new or factory-direct parts.
Also, especially with providers like AutoShack, you can often buy in bulk or in bundles at a reduced cost. Alternatively, if you only need a single control arm, you can find that as well.
And as a bonus, most local mechanics will install aftermarket parts into your vehicle if you bring them along. It should be noted that dealerships will rarely use aftermarket parts even if you bring them in yourself, as they are obligated to install factory-fresh parts into your vehicle.
AutoShack keeps your ride smooth
At AutoShack, we offer a wide selection of control arms and suspension parts for sale at low prices.
Our inventory is easily searchable; all you have to do is plug in your vehicle’s make, model, and year into our search bar and our system will display all the relevant parts we have available.
Shipping is fast and easy with AutoShack. We offer free shipping on most orders and offer expedited shipping for those critical rush jobs.
Stop by our website today and browse our catalog to see what AutoShack can do for you!