Constant velocity joints, better known as CV joints, are found in front-wheel-drive cars. The joints are attached to each of the vehicle's front wheels. Their purpose is to transfer momentum to the wheels at a constant rate as well as secure the movements of the car's suspension mechanism. If CV joints break, the car will stop working. It's important to spot the signs of a failing CV joint so you can replace it before further damage occurs.
Clicking Noise While Turning
A key sign of a failing CV joint is a clicking noise when you turn the wheel of the car. To test this, manoeuvre the car in a large space. Reverse the car in a circle by turning the wheel completely in one direction so that it's on full-lock. While the window of the car is open, listen to any noise coming from the front wheels. A failing CV joint will click loudly during this manoeuvre.
When the car changes speed, a failing CV joint makes a clunking sound. A clear sign of this is an increase in "clunking" when the vehicle travels in reverse. Check this symptom by accelerating and decelerating the vehicle while going backwards. If the sound becomes more prominent, it could indicate a failing CV joint.
Vibrations when Accelerating
Another sign of a failing CV joint is a vibration or shake when the vehicle accelerates. This is caused by an imbalance of weight between the two front wheels. Check this by driving on a quiet, clear road. Accelerate the vehicle quickly from a stopped position. You will be able to feel the any unusual vibrations or movements through the steering wheel of the car.
Split CV Boot
A CV boot is a rubber part that surrounds the CV joint and protects it from dust, gravel and other debris on the road. If a CV boot splits, your car's CV joint could fail because it is not fully protected. You can recognise a split CV by getting underneath the car and looking directly at it. Look at the rubber that is covering the driveshaft adjacent to the front wheels of the car. Look for splits, tears or holes in the rubber. Place a finger on the inside rim of the boot and feel the grease. If it is gritty or rough to the touch, this indicates that the CV joint might be failing.
Internal Joint Damage
A CV joint features interior balls that slide along grooves, helping the mechanism work. If a CV joint is failing, one indication is that the surface of the balls has knocks, marks, dents or holes. Also, the balls should fit securely and neatly into place. You can check the condition of the balls by removing the CV joint and examining it.