The upper ball joint is an important component of a motor vehicle’s suspension system. it works in a similar fashion to the hip joint of a human being. Depending on the make and model of the vehicle, there are either two or four ball joints. If there are only two, these are located at the bottom of the wheel hub. The upper ball joint is present in vehicles with a “shock and springs” suspension system.
The upper ball joint is made from a metal ball that is contained in a metal capsule. The upper ball joint can move horizontally, vertically and can also rotate, acting as a shock absorber. The upper ball joint is almost always fitted to the front suspension only, although in some higher model vehicles they are also fitted to the rear suspension.
Upper ball joints become worn over time, as with most motor car components, especially if their rubber casing cracks, allowing lubricant to leak out or dirt and/or water to get in.
Indicators that an upper ball joint may have suffered damage and lost its effectiveness are the existence of a banging noise when the car travels over uneven roads, steering problems and excessive wear on the edges of the tyres.