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All you need to know about ball joints

As amazing as it may sound, the way your vehicle steers into and out of corners has a lot to do with how we are built as people. To make the wheels turn left or right, a steering system uses a ball joint similar to the one connecting your hip to the leg. Of course, bone tissue isn’t used in cars, but the working principle is very much the same.

How suspension ball joint work

Ball joints connect the steering knuckle to the suspension arm of the vehicle. The two-plane motion done by the ball joint is highly important, as it allows the joint to absorb almost all mechanical shocks generated by potholes as well as other wheel movements generated by road irregularities. Also, the weight of the vehicle is supported by these rather small elements called ball joints.

ball joint scheme

Types of ball joints

Depending on the vehicle type, front suspension may feature single or double ball joints. While some cars come with just lower ball joints, more advanced units also feature an upper ball joint that takes on suspension efforts, allowing for a better steering process as well as increased reliability. Even in this case, the lower ball joint is still the one carrying most of the load generated by the weight of the vehicle pressing on the wheels, while also absorbing shocks.

Upper/Lower Ball-joints, and Control Arm bushings

Suspension Type
Upper Ball Joint
Lower Ball Joint

Both upper and lower control arms with spring on lower control arm

Non-load carrying

Load carrying

Both upper and lower control arms with spring on upper control arm

Load carrying

Non-load carrying

McPherson struts

Non-load carrying

Non-load carrying

Diagnosing malfunctioning ball joints

As mentioned above, ball joints are subjected to a lot of forces and torque, thus also being prone to wear. Ball joint damage should be addressed before complete failure since in such cases not only the joint itself damages, but it will also create issues with other connecting suspension elements. Suspension arms or steering knuckles can get misshaped due to ball joint failure, as well as the tire.

ball joint problems

The first symptom that is most likely related to ball joint damage is uneven tire wear. If you notice your tires wearing non-evenly, then your vehicle’s upper or lower ball joints may be malfunctioning. Other symptoms including clunking noises while driving over road irregularities or when turning or having the vehicle pull left or right even if you are not turning the wheel.

Whatever the case may be, ball joint damage symptoms are very obvious and could endanger your safety while staying behind the wheel. Taking this into consideration, here is how ball joint problems can be fixed.

Repairing ball joints

Since they don’t feature disassembly possibilities, ball joints cannot be repaired, just replaced. Again, depending on the age, type and manufacturer of the vehicle, the costs of replacing faulty ball joints can vary between a few hundred dollars up to over a thousand. A good thing to remember is that you don’t need to have all ball joints replaced at once; replacing faulty ones is enough, as long as a wheel alignment process is undergone right after that, to ensure straight steering and uniform tire wear.

ball joint removal tool

Although you may be a great DIY person, replacing car ball joints is something to be done inside a specialized service unit. Tools like presses and other specific devices need to be used for a correct ball joint replacement procedure.