A wheel bearing for a vehicle.

How to Identify Bad Bearings

Bearings allow smooth rotational movement between two metal surfaces. They come in different styles and fit different applications, operate in places like hub assemblies and driveshaft components, and are buried inside the engine and elsewhere. Because of the vital role bearings play enabling movement, the consequences of failure can be major. Know the signs of bad bearings to avoid serious damage and potential breakdowns.

Bearing in Mind

We’ll focus on wheel bearings here. These ride snugly between the end of the axle and the hub assembly, allowing the wheels to turn freely while remaining in alignment. They require lubrication, and must be occasionally repacked with grease to do their job. Without them, the metal surfaces would be in direct contact while moving at high speeds, causing friction and heat to skyrocket. Too much heat and the bearings will wear, warp or break, followed by neighboring components, all the way up to losing an axle while driving.How to Identify Bad Bearings

Roll Play

Some symptoms of bad bearings can be identified while driving. Keep in mind that bearings will give different signs of failure as the severity of the problem progresses, so early identification is key to damage reduction.

One of the first things people notice is noise, which can be varied. A humming sound coming from the wheel area that increases with speed is one indicator. If it’s more of a grinding, the problem is worse. Try to identify which side the noise comes from, as it’s unusual for both sides to fail at once. A quick trick for this is to turn slightly in both directions while the car is moving and listen. The problem is usually on the side opposite the direction of the turn when the noise occurs.

Pay attention to drive feel. Vibration of the steering wheel at low and high speeds, vibration of the vehicle, a tendency of the vehicle to pull to one side and loose steering (uncharacteristically slow response) can all be red flags. They may also result in uneven tire or brake component wear, so monitor that as well … as you should be anyway.

Bringing to Bearing

If you’re able to safely jack up and secure the vehicle according to manufacturer direction, there is further testing you can do. With the vehicle turned off and wheels off the ground, try turning the wheels by hand, checking for noise or binding. Next, grab each side of the tire and try to wiggle it back and forth. Excessive play here means the bearings are shot and need immediate replacement.

As a rule, if a bearing is bad on one side of the axle, replace both it and the one on the other side. And remember that many of the symptoms above can be the result of other root problems, so be on the lookout for signs, but always have anything unusual checked out by a professional for a proper diagnosis. As with other car problems, don’t expect things to fix themselves or get better with time: Stay safe by paying attention.

Check out all the steering and suspension parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on bad bearings, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Blair Lampe.

about author

Blair Lampe

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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