Automotive Q&A

Answer: Constant velocity, or CV, joint boots cover and protect a very important part of your vehicle’s driveshaft, your CV joint. Before we get into what the boot does, let’s discuss what a CV joint really is. CV joints are used to connect your vehicle’s transmission to your wheels. They are part of the driveshaft and are used primarily on front-wheel drive vehicles, but they are also used in rear- and four-wheel drive vehicles. Each drive wheel has two CV joints: the inner joint connects the transmission to the axle and the outer joint connects the axle to the wheel. The CV joint’s name comes from its ability to move with your vehicle’s suspension in any direction (if your vehicle hits a pothole or an uneven surface) and still be able to keep the drive wheels moving at a constant velocity. The CV joint is a very special joint: it connects two different rotating shafts. These two rotating shafts are stuck in a fixed position; so, the CV joint must be able to move and bend to keep these two shafts connected. CV joints are being used in newer vehicles and are taking the place of the old “U” joints. The CV joint is able to transmit even levels of torque to the wheels continually no matter what angle the joint is in. This means that no matter how many potholes you hit or if the vehicle is turning, the CV joint will keep the drive wheels moving at a constant velocity. Now that we know what a CV joint is, let’s discuss the CV joint boot. These boots have a very critical job; they must house and protect the joint. These boots are made of strong rubber that is able withstand the amount of bending the joint does. The boots keep the joint’s lubricating grease inside and clean. The boot also protects the joint from wet roads and other debris.