Signs Your CV Shaft Is Bad! Uh Oh!
Signs your cv shaft is bad can be all over the place. The central velocity shaft (cv shaft/axle shaft) is a core component that links the transmission drive gear with your wheels.
Signs that your cv shaft is bad will include humming, potential axle grease inside of the wheel well/tire, no vehicle movement when applying gas pedal, and grinding/clicking noises.
We will show you today how to diagnose this concern and talk about getting it fixed!
An Obnoxious Hum!
When cv shafts go bad they typically produce a humming noise. If you are cruising down the road and hear any humming/clicking/grinding noises, you might have a bad axle shaft.
Checking it can actually be pretty simple if you hear something audible. Start by making sure it isn’t your wheel bearing/hub assembly.
While the car is in the air via lift, jack, jack stands, etc… grab the tire and try to wobble it left to right. If there is play you might need a new hub assembly/wheel bearing instead.
If it is not your wheel bearing then we need to do a further diagnostic. This is where checking for grease/leaks comes into play.
So Much Grease…
Typically when a cv shaft fails, grease comes out. These are lubricated just like a tie rod. There is a easy to see axle boot with a clip on each side. When the axle shaft fails it can be because the boot has ripped/torn allowing dirt inside.
As the tires/wheels spin this also rotates your axle shafts. We get moving at pretty high speeds sometimes which causes it to fling grease all over the place. Most of the time without even jacking the vehicle up you can see this grease.
Pay attention to your tires/wheels and give the inside of the wheel well a good inspection too. The wheel well is the area where your fender comes down. It usually contains a plastic shield to prevent any dirt from getting up in the fender.
If you have found your cv shaft boot to be torn, it is highly recommended to just replace the entire cv shaft.
The Car May Not Move.
Your axle shaft is connected to the intermediate shaft and transmission. As you get your car moving, this axle shaft rotates inside of the hub assembly which then rotates your wheels. There are little metal clips and hardware on the inside of the cv shaft.
If you remove the clips and then the axle boots, you can see the internals of your cv shaft. These internals can break which will cause the axle shaft to no longer rotate. This leads to 1 tire attempting to still spin while the other will not move at all.
When this happens, you will hear a very audible grinding/humming noise. This is a sure sign that the axle shaft has failed due to the internals going out. These sometimes can be rebuilt but it is easier just to replace the entire cv shaft assembly.
The signs your cv shaft is bad are pretty clear to understand. We didn’t just want to give you those tips though, we also wanted to explain the general process of how one is removed/replaced.
On most cars (process will be different based on vehicle) you can actually get the cv shaft out pretty quickly.
Start by safely raising the vehicle and remove the tire from the side you are working on. After you have removed your tires and such you will need to remove your brake system.
Remove your caliper by removing the 2 caliper bolts holding it to the caliper bracket. Once these 2 bolts are removed you can remove the caliper and slide out your brake pads.
Never allow your brake caliper to just “hang” from the brake hose. This can damage the brake system/hose.
From here you will want to remove the next 2 bolts from the caliper bracket.
The bracket will be bolted to what is known as the steering knuckle. This is where your hub assembly and axle shaft rest in. Once the caliper bracket is removed, you can also now just slide your brake rotor off as well.
From here you will want to loosen the front axle nut. This one can be tricky as it’s on there pretty tight. Once you back off the nut a little bit, get it to the point where it’s almost off the cv shaft. Don’t be alarmed if the axle nut looks pretty large, they are usually a 30+mm.
From here you can remove the 3 bolts that hold the wheel bearing into the steering knuckle. Once these are loosened and removed, you will have to remove the hub assembly.
Sometimes the removal of the hub can be tricky. They somewhat “press” themselves into the steering knuckle. When this happens you will have to use a hub assembly puller, or if you have a new hub to replace with it, just smack the back side with a hammer to push it out.
Once the hub is out you are ready to remove the cv shaft.
Axle Shaft Removal.
To remove the cv shaft, you typically only need to use a pry bar. Get towards the transmission end or intermediate shaft and just pry backwards.
You will want to be past the second axle boot, when you apply this pressure the cv shaft should let loose and come right on out.
Once it out, give it a good visual inspection and check for grease, tears, or busted clips.
Installation is the exact same procedure just reversed. Slide the new axle shaft into the transmission/intermediate shaft. It may take a little bit of force and shoving, but you will get it in. Just make sure your splines line up and it shouldn’t be to hard to put in.
Once you have it installed in the transmission, go ahead and grab your hub assembly. Slide the cv shaft into your new hub and then bolt the hub into the knuckle. Once the hub is in place now is the time to install your axle nut.
Important note: When you get the axle nut “snug” make sure you come back around with a torque wrench and torque it down to manufacturers specifications.
With the axle nut tightened down you can now install your brake rotor, caliper bracket, brake pads, and then finally the brake caliper.
If your vehicle also came with abs, make sure you also feed the wire correctly and plug it back in.
Put your tire back on and give it a good test run. You should at this point now have installed not only just a cv shaft but also a wheel bearing! Job complete!
If you enjoyed this post or need more good tips, don’t forget to check out our guide on uneven pad wear.