Let me start by saying that your wheel bearings keep the wheels on your vehicle. Did that get your attention? In this article we’ll discuss more about wheel bearings and how you can keep them doing their very important job.
Wheel bearings are pretty simple parts. They’re made of high quality steel and are engineered to last 100,000 miles or more if properly cared for. The bearings do two very important jobs: First they allow the wheel to freely rotate with as little friction as possible. Second, they support the weight of the vehicle. For example, if your car weighs 3,600 pounds, each wheel has to support approximately 900 pounds. That’s a lot of heavy lifting over many, many thousands of miles.
Even though wheel bearings are relatively simple, they need to be in near perfect condition to do their job. The bearings are packed with heavy grease to lubricate and protect them. A seal keeps the grease in and water and dirt out. It’s when the seal starts to leak that problems begin. The grease can become contaminated; causing the wheel bearings to overheat and ultimately fail.
The first sign that your wheel bearings are in trouble is an unusual noise coming from a wheel. It could be a chirping, growling, rumbling or a cyclic sound. The noise could get louder or even disappear at certain speeds. Your technician can inspect for bearing wear by lifting the vehicle and checking for play in the wheel.
Now some wheel bearing assemblies are factory sealed. That means that they cannot be serviced – they can only be replaced. Those that aren’t sealed can be serviced on schedule. The bearings are removed, cleaned and inspected. If the bearings are still good, they’re re-installed – if not, they’re replaced. They are then packed in grease and a new seal is installed.
If your vehicle has a factory sealed wheel bearing assembly, the entire assembly needs to be replaced when trouble arises. Unfortunately, the parts are pretty pricy – but they usually last about 150,000 miles as long as the seals hold up.
Now, even a good seal cannot keep out water that’s exerting pressure on the seal. So if you’ve driven through hub deep water your bearings should be cleaned and repacked if they’re serviceable. If you have factory sealed bearings, you just need to watch for signs of premature failure.
If your wheel bearings can be serviced, your owner’s manual will recommend an interval, usually around 30,000 miles.
Now, if you have any sort of trailer, don’t forget its wheel bearings. They probably need to be serviced even more frequently. This is especially true for boat trailers that are used to launch the boat by backing it into the water. These should be serviced every year, usually at the end of the season so that the bearings don’t have the opportunity to sit and rust all winter.
So what happens if wheel bearings fail? Well, the wheel can literally fall off the vehicle. I don’t need to tell you how bad that could be. So check with your service adviser and see if your vehicle’s wheel bearings can be serviced and when it’s recommended. Listen for warning signs. If you’ve been fording streams or puddle surfing after rainstorms, be especially vigilant.