Your car's CV boots stop dirt and other mess getting into your driveshafts' joints, but they can and do fail. So how do you check if they’re in rude health?
A car's CV boots, also known as driveshaft gaiters, are nothing more than little rubber socks that cover your driveshafts' joints. They’re a £5 part at best. But don’t let their innocence belie their importance.
Under those boots are, at one end, an input shaft and at the other (in the most common case of front-wheel-drive cars) a constant velocity joint (aka CV joint).
Without boots, these grease-laden moving parts would become thick with dirt and filth that would go on to wear the driveshaft away.
Furthermore, worn CV boots as they’re otherwise known, are an MoT test failure.
How do you check the condition of CV boots?
1) Raise the vehicle
You’re not going to get decent access while the car is on the ground, so get it jacked up and in the air. Once up, take the front wheels off – this should give you decent access to the CV boots.
2) Give the CV boots a clean
The CV boots are probably going to be thick with road dirt and filth. You can’t inspect anything in that, so take a soft brush to them – be careful not to damage them before you've even checked them!
3) Turn the wheels
For the outer CV boots, turn the steering full lock, which will give you better access to get your head behind the wheel hub where you’ll be able to see the boot.
4) Present and correct?
CV boots are held in place by circular clips, either metal or plastic. Check these first. If they’re still present, correct and tight that’s good. If they’re missing, there may well be dirt within the gaiter. Replace a missing tie ASAP, but not before pulling the gaiter back to check there’s nothing in there but grease.
5) Grease is the word
At the inner (gearbox) end, check for any signs of grease leaking. Again, check the ties and that they’re holding the gaiter tight and in place.
6) Feel the CV boots for damage
The CV boots are rubber, and rubber is pliable. So get in there, pull them, twist them and look into the crevices. Look for any signs of cracking or cracked rubber and for splits and cracks. You won’t see these in situ - you need to get your hands on the gaiters.
7) Clean, road test, repeat
Finally, if you can’t see anything awry, but you want to be sure, take some photos of the CV boots with your phone. Go on a long test drive, making sure to stay on clean roads, and then have another look.
On the test drive, be sure to do lots of tight turns to really flex the boots. If there are any grease spots when you look again, you know your gaiters are weeping. Simple.