Modern cars are incredibly complex things, a fact we've stated over and over again. However, while cars continue to evolve year after year, some things have been fairly consistent since the dawn of (automotive) time.
There's actually quite a few reasons that a car might make clicking noises when turning but, as you might have guessed from the title, CV shafts are a pretty common one (and are also one of those consistent things throughout history).
So, what is a CV shaft?
Well, a CV shaft (or a driveshaft) is just a way to transfer rotational energy from an output to an input. For the normie's amongst us, it's just a rod that's used to turn a thing.
A rod that turns a thing is just a shaft that drives and object hence why we call it a driveshaft. However, if that's the case, why are we suddenly calling them by a different name? Shouldn't we just call all CV shafts driveshaft?
Kind of yes and kind of no.
Even though all CV shafts are a kind of driveshaft, not all driveshafts are CV shafts.
In the automotive sense, a driveshaft is most often used to transfer power to something that is in line with the original object. They often have universal joints to allow for movement in one direction but, it's fairly limited to it's range of motion and causes the output speed to variate with each rotation (which can cause vibrations).
On the other hand, CV shafts have a special kind of joint (a constant velocity joint) which allows for motion in multiple directions easily while not causing any variation in output speed.
So why do CV shafts start to click?
Simply put, it all comes down to wear. Because these joints transfer a significant amount of power, they are quite heavy wear items. To combat this, manufacturers have encased them with a grease filled rubber boot but, over time these boots get damaged or split which allows the grease to escape.
This lack of lubrication (often teamed with the ingress of road grit) causes wear to the joint and excess play at extremities which in turn causes a clicking sound.
So what is the solution?
The best solution is always prevention and, regular servicing and checks of the CV boots can prevent these joint from running dry of grease.
However, if you're car is already clicking when turning, you may need to replace the CV joints or CV shafts.
If you have any questions about this blog post, would like a second opinion from a mechanic or would like to find an honest mechanic in Brisbane, check out Kashy here.