CV joints and their protective rubber boots should be inspected frequently for signs of wear. In fact, technicians should make it common practice to inspect the halfshafts whenever a vehicle is hoisted on a lift. 

On front-wheel-drive (FWD) applications, two CV joints are used for each halfshaft. The CV joint closest to the transaxle is called the inner joint, while the one closest to the wheel is the outer joint. Under normal circumstances, CV joint and boot services usually fall under the catchall instruction "inspect," and do not require routine maintenance.

Faulty boots are the most common cause of CV joint failure. The accordion pleats often hide cracks and tears that eventually turn into serious leaks, allowing grease to be thrown out of the CV joint by the centrifugal force of axle rotation. Regular inspection can turn "scheduled maintenance" into "preventive repair" if you find a cracked, torn or otherwise damaged boot or a leaking transaxle seal.

The outer joints fail most often because they're close to the wheel and road surface. In addition to inspecting the boots for cracks and other signs of damage, look for leaking grease, and loose or missing clamps. Also look at the transaxle lip seals at the inner CV joints for signs of leakage. If you find evidence that a boot or joint is damaged, this does not necessarily mean the rest of the joints require service. However, if you remove a halfshaft for service, consider the preventive benefits of replacing the boot at the other end of the shaft.

The chart below lists symptoms and possible causes for common CV joint problems.