What Is a CV Joint (Constant Velocity Joint)?
Constant Velocity joints are located at both ends of the front driveshafts (and rear driveshafts on four-wheel-drive and all-wheel-drive vehicles). They allow the shaft to transmit torque at a constant rotational speed even when the shaft is operating at an angle — essential at the front wheels which must also steer. CV joints are packed with grease and enclosed in a rubber or thermoplastic boot that must remain intact to retain the grease and exclude water and dirt.
What Does the CV Joint (Constant Velocity Joint) Do?
In a front-wheel-drive vehicle, the driveshaft must transmit engine torque to the front wheels while those wheels are simultaneously steered — meaning the shaft is operating at an angle of up to 45 degrees on full lock. A conventional universal joint transmits speed unevenly at such angles, causing vibration. The CV joint solves this with a ball-and-groove design that maintains constant torque transmission regardless of operating angle.
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Get My Free Fault Scan →Symptoms of a Failing CV Joint (Constant Velocity Joint)
The classic symptom of a worn outer CV joint is a clicking or clunking noise that occurs specifically when turning — particularly on full lock at low speed. This noise is typically heard when manoeuvring in car parks or making tight turns. An inner CV joint failure more commonly causes vibration under acceleration. A torn CV boot is often detectable by grease thrown onto the inside of the wheel arch before the joint itself fails.
When Should the CV Joint (Constant Velocity Joint) Be Replaced?
CV joints are replaced on failure. A split CV boot should be replaced as soon as it is noticed — before water ingress destroys the joint itself. Boot replacement costs £60 to £120; complete driveshaft replacement costs £150 to £400 depending on the vehicle.
If you are experiencing symptoms related to your cv joint (constant velocity joint) and are unsure whether it needs replacing, a free MotorLoom fault scan can help identify whether the component is likely at fault - giving you the most likely cause and estimated repair cost before you visit a garage.
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Related Parts
Other components that work alongside or are related to the cv joint (constant velocity joint):