Constant velocity joints, or CV joints, are an integral part of most automobiles. They are primarily used to control steering. CV joints are located near the suspension mechanism for each wheel. Like any other part of a car, a CV joint can deteriorate and require repair or replacement. Due to its specialised function, the symptoms of a CV joint problem are specific and often easy to diagnose.
Many of the problems created by a malfunctioning CV joint are confirmed by noise. A common symptom of a poor CV joint is a popping or clicking sound. Since the CV joint is affected by steering, this sound is often louder during a sharp turn. Driving in reverse may further increase the sound.
Significant changes in speed may create a strong "clunk" sound from several different problems within a CV joint. This sound may come from either acceleration or deceleration. Because the CV joint is structured around the wheel, other faulty mechanisms may also create similar noise, so diagnosis can be tricky. Similar to other CV joint sounds, if the clunking noise presents more clearly during reverse gear, the CV joint is likely to blame.
One part of the CV joint is the "boot" that protects the inner workings of the CV joint. The boot keeps grease inside the joint from leaking out, and also prevents outside elements, such as grass and dirt, from getting inside the joint. If the boot fails, grease leaks will show up and the CV joint will lose much of its lubrication, resulting in joint failure.
Several different forms of vibration may result from a CV joint problem. As with other CV joint symptoms, the vibrations may present with increased speed or acceleration. However, vibrations can be caused by other faults in the vehicle as well, so the CV joints are not necessarily the issue. If other remedies, such as wheel alignment, do not solve the problem, consider a careful inspection of all CV joints.
CV joints must be properly inspected and repaired at the first sign of any symptom. A CV joint left unattended can cause significant damage to other aspects of the vehicle. Drive shafts and axles often require replacement due to problems originating with a faulty CV joint. In extreme cases, the vehicle can stop running altogether.