The subject of wheel bearings is already rather deep in the subject of car maintenance. Ordinarily, we just cover simple topics like tuneups and oil changes. But if you intend to keep your car for a decade or more—or drive it more than 100,000km—you’ll need to learn about this part.
Wheel bearings can’t be seen, and thus, not much attention is really given to them. But they’re there, and they’re important. Every time you use your car, the wheel bearing inside the hub takes the entire weight of your car, its occupants, and whatever cargo you’re carrying.
Bearings are devices that reduce friction in mechanical devices that rotate. Your car’s wheels rotate, and wheel bearings help them move smoothly with the least amount of friction. These bearings are located in the hub to which the wheels are bolted. That hub is then bolted to the vehicle’s suspension. Wheel bearings that are in top shape are very important to the smooth operation of your car.
The bearings are made up of many small steel balls rolling within metal rings packed with grease. After many kilometers of use, they wear out because the grease dries up and wears out.
There are many factors that can accelerate the wear of wheel bearings, driving your wheels through flooded streets being one of them. Although bearings these days are ‘sealed,’ that doesn’t mean they’re waterproof. Driving through deep waters can shorten their life because the petroleum-based grease inside them doesn’t mix well with water. Other factors that accelerate bearing wear include driving on bad roads or with unbalanced wheels.
Once wheel bearings wear out, you’ll need to take them out for replacement. In some older cars, these bearings may be cleaned up and checked for wear. In case they’re still serviceable, they are repacked with fresh grease. However, those of the sealed variety fitted in most cars these days are simply replaced.
There are two ways to tell if your bearings have gone bad: by sound or through a wheel wiggle test. Check them out below:
When bearings go bad, the grease inside has usually dried up. Once this happens, the small steel parts inside—the small steel balls and the rails they roll around in—corrode. Because of this, the wear on the bearing is accelerated, and there’s greater friction in its operation.
Sometimes, the wear and the friction create an audible sound that’s much like tire noise or the howling of wind. The sound comes on quite gradually that you barely notice it. What you do notice is that your car isn’t as quiet as it was as when it was new.
Other times, a bad bearing doesn’t even make a sound. But to test whether a bearing has gone bad, you can either put your car up on a lift or put it up on jack stands, then grip your hands on either the 3 and 9 o’clock or the 6 and 12 o’clock positions of the tire, then try to wiggle the wheel back and forth. If the wheel does wiggle, chances are it has a bad bearing or bad suspension pieces like ball joints or tie-rod ends.
To check if bad suspension parts are the source of wiggle, you’ll need to observe the ball joint and the tie-rod end behind the wheel as you perform the wiggle test. Have someone look behind the wheel as you do perform the test again. If there’s no movement seen in the ball joint or the tie-rod end, you definitely have a bad wheel bearing that needs replacement on that wheel.
When installing new parts on a car, it’s always best to use high-quality aftermarket or OEM parts. Going with low-quality components may be less expensive, but these items may fail prematurely and not last as long.