What is a CV Joint and what does it do?
So a few months back I was happily cruising along a scenic 4x4 track out in Mundaring when I noticed, what I thought at first to be, a flat tyre. Upon inspection I found nothing appeared to be wrong with my tyres, so I started to consider the possibility that my wheels where perhaps out of alignment and continued on my way with a slight wobble through my steering wheel.
Hitting the blacktop it became quickly apparent that something was seriously not right with my cars performance, and pulled over to have a closer look.
Looking under my car I quickly discovered the issue, my CV boot was torn and my day of 4 wheeling had added to the issue by packing the (now) exposed joint with mud, water & sand!
I limped the car home, which luckily was only 30 or so kilometres away and cleaned the joint to get a better look.
I've had this issue before in the past, however I luckily noticed the damage early and the only repair required was a replacement CV boot. This time however was much more serious as the CV joint itself had been damaged (the audible clicking noice of a failing CV gave this away!) so I called my mechanic Chris over at AutoplusWA in Midland and booked it in for repair.
Now I'm sure there are a lot of you out there who have the tools and mechanical knowledge to repair a CV joint, and perhaps have had this issue occur and have even repaired it off-road (there are a heap of videos on YouTube on this very topic) but for us mere mortals this is a job for a professional.
Ok, so long story short, my CV joint has been replaced and I'm happily back driving and 4 wheeling, but this experience left me wanting to know more about CV's and what they do.
Chris was kind enough to shed some of his expert advice on this subject and offered the following advice that I thought I'd share with you all, so here we go.
What is a CV and what does it do?
"The CV joints job is to transit power to the wheels at a variable angle without any loss of rotational speed."
Do all makes of 4WD's have a CV, what other types of axels are there?
"Not all 4x4's use a CV shaft with two joints to drive the front wheels. Some use a solid axle that is in the diff, it will still generally have a CV joint however it is housed inside the swivel hub assembly. Generally 4x4's with independent front suspension will utilise a CV shaft assembly with two CV joints."
What causes a CV to fail?
"There are two more common causes of failure of CV joints. One is due to the vehicles being raised, this changes the angle that the CV joint runs at and can cause premature failure by the inner rollers sitting in the wrong spot or the boots being over stretched and popping off. The other is due to failure of the CV boots either from a raise or wear and tear. The boot is there to keep the grease in and the dirt out! As soon as the boot splits it will start spitting the grease out of the joint, if we then take it off road and let water, sand or mud through the split in the CV boot which then ends up bonding with any remaining grease which is a recipe for a grinding paste that is going to wear the joint out in no time."
Note: Chris explained the two main causes of CV failures, most of us four wheel drivers run either larger than "stock" tyres or fit a lift kit which puts our CV joints at a compromising angle. Secondly we spend a lot of our time driving in sandy and muddy conditions that combined are your CV joints worst enemy.
What can we do to prevent CV's prematurely wearing out?
"You can install a diff drop or spacers if you have raised your vehicle or the most simple thing you can do yourself is always ensure your CV boots are in good condition, if they're not, get them sorted before your next trip!"
Note: I am my worst enemy when it comes to checking my CV boots regularly, if I had noticed the damage to my boot earlier all that would have been required would be a new boot. Instead the whole joint need replacing along with a new boot of course.
What should we be looking out for when it comes to CV’s before an off-road trip?
"Inspect all the boots have no tears or splits and their clips are secure."
What happens when a CV fails?
"Generally, when a CV starts to fail it will give you a click noice when turning. This gives you an indication the joint is failing. If it bypasses the click and goes straight to failing (usually a snapped joint or shaft) you will loose drive to that wheel. In 2WD vehicles due to the nature of differential set up you will loose drive all together."
If my CV joint is making a noice does it need replacing?
"If it's noisy it's giving you a heads up to get it done, don't take your 4WD on any serious off-road trip without having it replaced first or failure could leave you stranded with the use of 4WD."
Is a CV joint easy to replace?
"It depends on your set up, if you have a solid axle with a swivel hub for instance, it's going to take more effort to get it replaced."
How much does it cost to fix a CV?
"The cost can vary anywhere from $300 to $1000 depending on how much you decide to do at the time, for instance, you might opt to do a swivel kit, wheel bearings and driveline oils at the same time. Your mechanic will be in the best position to advice you of what should and shouldn't be done at the time of replacement to keep your machine at it's best."
So there you have it, thanks to Chris Notte from AutoplusWA.
Oh, and by the way, this is not a sponsored post nor do I have any financial ties to AutoplusWA. I just like to give credit where credit is due and am continually impressed by the level of expert advice and workmanship that Chris and his team provide. If you're looking for reliable, honest and friendly mechanics give them a call on 9274 7311 or head to their website autopluswa.com.au, and you can thank me later for putting you onto them!
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