What is a C/V axle?
The C/V Joint or C/V axle refers to a constant velocity joint or axle. The C/V Joint is part of the drive shaft that attaches your vehicles wheels to your transmission or transfer case. There is typically a C/V Joint at both ends of this axle shaft (inner and outer C/V joints). CV joints are designed to be able to bend in any direction your suspension, steering, and wheels may be moving. CV joints are primarily used in the drive shafts of front-wheel drive cars due to the ability to maintain a constant drive force at the wheels while at the same time accommodating for different kinds of movements in the suspension and steering of the vehicle. For this reason the CV joints and C/V axle are also now being used in newer All-wheel drive or four-wheel drive cars. We see a lot of Subaru vehicles using C/V axles in the front and rear of the vehicle. Below is a picture of a C/V Axle (Fig A.) The second image shows just the C/V Joint with the boot removed. Notice the C/V Joint Ball Bearings that are now exposed. Imagine these joint being exposed to rain & the elements as happens when the C/V boots tear. (Fig B.)
C/V Joints The Heart of the C/V Axle:
CV joints should be inspected periodically as it contains components that wear. A C/V joint is covered with a rubber boot that tends to deteriorate over time or can be damaged by road debris. At A+ Japanese Auto Repair the most common issues we see with a C/V axle is torn C/V boots. When a C/V tears open, cracks all the way through it quickly expels the grease lubricating the joint. The expelled grease sprays under the vehicle and around the wheels involving some heavy duty cleanup. In some cases we have witnessed in our service bays C/V grease on braking components. Also, when the boot tears the C/V joint is left exposed to the elements with no lubrication. If the CV axles are inspected periodically, torn boots can be replaced as needed, potentially extending the life of the joints and C/V Axle. As you can see in the picture on the left, there are many parts moving in different directions in your C/V axle. The C/V axle is spinning just as fast as your vehicles wheel spins and moves up and down with all the bumps, potholes and dips in the road. This is one part that takes some serious abuse and rolls with it!