Basically, the Control Arm is what holds the wheel to the car. But allows it also allows the vehicle to move up and down while keeping it straight-up. The control arm is attached to the frame of the vehicle and the steering rack. It will typically have 3 contact points, making an "A" shape and using a Ball Joint to connect to the steering system. While some control arms allow you to change the ball joints separately, almost every control arm sold by AutoPartsNerd will have the ball joint already attached. So the control arm is included more likely than not as one of the parts. Some European vehicles are best known for using uncommon control arm setups. For example, some Audi's can often have four control arms per wheel! So that's something to keep in mind if you drive one of those vehicles.

There are generally two reasons why you would need to replace your vehicle's control arms. The first being if there is physical damage to the control arm itself. But it's important to note that control arms are constructed with iron, and even aluminum in some cases if you purchase performance control arms. In either case, while it's not impossible, they are usually very difficult to damage. The more common and second reason is the ball joint or control arm bushing becoming worn out and failing. Both of these parts can not always be removed and replaced. So even if you determine that one of these two parts is the problem, you might still have to purchase and replace the control arm.