How to Inspect Your Vehicle’s Axles
One of the common tasks that mechanics typically perform when you bring your vehicle in for service is an axle inspection. Auto maintenance and repair specialist The Humble Mechanic shows you how to perform this simple, visual inspection that may allow you to identify needed repairs before they potentially become larger and more expensive.
Hey everybody, its Charles from HumbleMechanic.com. Today I’m going to show you how to inspect the axles in your car.
A proper axle inspection is something that most mechanics will do anytime you bring your car in for service. But, this is something that anybody can do all on their own. And depending on how low to the ground your car is, you can do it with little to no tools. The only thing you’re going to need to do is get underneath your car.
Why would you want to do an axle inspection? Well, it’s really a good idea as just preventative maintenance. Oftentimes, you can catch a split CV boot before it becomes a much bigger and more expensive problem on your car. Typically though, when an axle fails, it can fail in a number of ways. Anything from clicking and popping while turning, to a vibration on acceleration or decel. Vibrations on excel or decel can generally point to either a bent axle, or a failure of the inner joint. Popping and clicking while you’re turning usually points to the outer joint failure. But, remember that failures can happen in any number of ways.
Before I show you how to inspect an axle, let’s talk a little bit about what an axle is. Now there’s other names for axles, including half shaft and CV axles — they are going to serve about the same function, and that’s taking the power output from the transmission and actually putting it to the wheels.
In addition to power transfer, the axle has to function in multiple conditions. On an axle on a front-wheel drive car, it has to rotate in order to take the rotating power from the transmission to the wheel. It also has to be able to compensate for changes in ride height, as well as your front wheels turning. So the axles are responsible for doing a lot on your vehicle.
There’s three main parts to the axle: There’s the outer CV or constant velocity joint; there’s the axle shaft itself; and then there’s an inner CV or constant velocity joint. These joints are packed with grease and covered with the boot of varying composition. That boot is meant to not only keep the grease in but keep debris and water out. Here we can see an axle attached to a wheel hub. As I rotate the wheel hub, you can see the joint flexing back and forth. And remember, not only does it have to turn left and right, it also has to rotate forward and backwards.
While the outer joint needs to be able to flex and turn with the turn of the wheel, the inner joint only needs to rotate and compensate for changes in ride height, as maybe we go over a bump or lean our car hard into a turn. Outer CV joints are typically a ball bearing style joint, while the inner joint is a little less complicated in its construction.
Now, if your vehicle is not tall enough to simply crawl underneath, you’re going to need to lift it off the ground. If you’re going to do this, be sure to use proper lift techniques, including chalking the wheels as well as using jack stands — please do not rely on a floor jack to hold the vehicle up while you’re underneath it. You can also use vehicle ramps and simply drive right onto them.
The easiest part of this inspection is going to be inspecting the boots. As you can see, the boot has ribs in it to allow it to flex and move with the vehicle. What we’re looking for here is any grease leaking, any holes, or any splits. It is not uncommon to see a split around one of the ribs of the boot. If you see any grease or any splits, you want to get that fixed right away.
And we’re going to do that same inspection for the inner boot as well. We also want to inspect the actual shaft. We’re going to look for any nicks, dings, dents, or any signs of something rubbing on it. If you were to see an even circular pattern around the axle, that means that something is rubbing it as its rotating. You can even check for play in the axle. Now, most vehicles will have a bit of play in these areas, so if you’re not sure, compare it side to side. We can also test drive our vehicle to check the axle as well.
We also want to make sure that while we’re underneath our car inspecting our axle boots, we inspect the clamps. A broken or damaged clamp can lead to grease leaking out of our boot or allowing moisture or debris to get in.
If you decide to tackle boot or axle replacement on your own, remember that a lot of vehicles may require a special tool or a number of special tools in order to do that job. So before you start, be sure you have the right equipment to do it.
All right guys, there you have it: a proper visual inspection of an axle. This can apply to a front axle on a front-wheel drive car. It’s very similar on a rear-wheel-drive car that uses this style of axle. The only thing that’s going to be different is the outer joint isn’t going to need to turn as the wheels turn. So, I hope that helped. I hope that takes some of the mystery out of a CV axle or half shaft inspection. It sounds a lot more intimidating than it really is. And even if you’re the type to take your car into a professional, at least you now have an understanding of some of the things that us professional mechanics look at when you bring your car in.
With that I’m going to wrap it up. If you have questions or comments about axle inspection, please post it down in the comments section. If you want to see more of my videos. Head over to HumbleMechanic.com and you can follow them all there. All right, guys. Hey, thanks so much for watching. Good luck on your axle inspections and I will see you next time.