Car Parts Basics: Wheel Bearing
Your car’s wheel bearings are key to the smooth operation of the wheels, but do you know how they work and how they might fail? Auto maintenance and repair specialist The Humble Mechanic explains wheel bearings and how to identify potential problems.
Hey everybody, it’s Charles from HumbleMechanic.com, and today we’re talking wheel bearings.
So, what is a wheel bearing? A wheel bearing is, quite simply, a set of balls or rollers that help your wheel spin freely and reduce friction. And this doesn’t just apply to cars – most things with a wheel have a bearing in it. Bicycles, trailers, wheel barrows, and more…generally have a bearing inside of it to allow the wheel to spin freely.
There are a handful of different designs of wheel bearings, but no matter the design, most wheel bearings will have: a housing, the bearings (either balls or rollers), a race (to contain them), a seal (to keep the grease in), some grease (of course), and some even have components for the wheel speed sensor, so the vehicle can know how fast that wheel is spinning, and in some cases, in which direction.
This one here is one complete unit, that bolts onto the car. While this style is individual pieces that need to be assembled.
When it comes to wheel bearing failure, the most common thing is going to be noise. This noise can come from a variety of things. What might seem like a slight impact to the wheel can cause damage to the bearing. Moisture getting in behind the seal, inside the bearing, can contaminate the grease and cause it to overheat. And like anything, an improper installation can cause premature failure.
The types of noise these failing bearings can create can widely vary: anything from a low growl to a high-pitched squeal, to even something that kind of sounds like a helicopter flying around in the back of your car.
There are a handful of ways to help isolate which wheel bearing is the one creating the noise. First, we want to start with a visual inspection and make sure there are no outside influences causing a problem with the bearing.
We also want to make sure it’s not another issue with the vehicle causing the noise, like improperly warn tires.
After the visual inspection, we’re going to move to a test drive. Step one is going to be getting the vehicle up to the speed when the noise is heard.
Next, we’re going to begin to isolate the location by loading and unloading the suspension. This is done by turning the steering wheel very slightly left and very slightly right. When we turn the steering wheel very slightly left, we actually load the right-side suspension of the vehicle. When we turn it right, we load the left side suspension.
As we load and unload the suspension, this can cause the frequency and pitch of the noise of the wheel bearing to change. In most cases, when we load the side of the failing wheel bearing, the noise will get louder.
When we unload it, the noise will get quieter. So, if we suspect a left-front wheel bearing failure, and we turn the vehicle slightly to the left while it’s making the noise, if the noise goes away we’ve unloaded that corner of the suspension. If we were to turn the vehicle to the right slightly, we’re loading that left side and making the noise louder.
Next, what we can do is check the play in the wheel. Secure the vehicle and properly lift it. Grabbing the wheel at the 12 o’clock and 6 o’clock position, pushing it in and out. Any play in the wheel here can point to a failure in the wheel bearing.
When it comes to replacement, often, DIYs are pretty easy and most of the time can be done with basic hand tools. A wheel bearing unit like this one has only a handful of bolts required to replace it. A unit like this one, where all the pieces are separate, can also be very easy. Some units do become a little difficult and require, either special tools, or a shop press to replace them.
Alright guys, I’m going to wrap it up there. Wheel bearing questions or comments? Feel free to leave them down below. If you want to check out more of my videos, head over to HumbleMechanic.com.
Alright guys, thank you so much for watching and I will see you next time.