A typical vehicle’s wheel suspension system has four ball joints – two sets, of upper and lower. These operate much like the hips in the human body, as a spherical ball bearing which moves in a cavity of equal size, allowing the wheel to move freely and conveniently. The mechanics will work smoothly as long as these upper and lower cavity sizes and bearings fit snugly, but will become unstable when one or the other is irregular or too loose.
You can tell if a ball joint, upper or lower, has begun to show signs of deterioration by a few telltale symptoms. If your steering does not feel as smooth and responsive as it once did, or new shuddering or jerking sensations develop when behind the wheel, this may be a sign of worn joints. Since this problem can quickly spiral out of control, be sure to have these symptoms checked as soon as possible.
It is generally an easy process to check if it is time for new ball, and a good mechanic will be able to quickly give a diagnosis using specialised tools. There is an acceptable amount of looseness allowed before being replaced, but when this level is exceeded a replacement should be made immediately to avoid dangerous driving conditions. It is important to keep in mind that some vehicle models have specific suspension requirements, and your mechanic should abide by them for best results.