A car's wheel bearings are what keep the wheels turning, so it's a good idea to keep them in top shape. With good maintenance and regular oiling, bearings should only need to be replaced every 30,000 miles, but when a problem occurs with them it is important to identify and fix the problem as quickly as possible so no lasting damage is done to the wheels, tires and brake system.
There are various symptoms of worn wheel bearings evident when you are simply driving along. A persistent squeaking noise could indicate the wheel bearings have dried up and are not assisting the tires. Poor handling is another indicator, as the worn out bearings cause increased wear on the tires. This may also be felt through braking, with the tires locking up. The most obvious symptom while driving is reduced coasting distances. When you take your foot off the accelerator but do not apply the brake the car will stop quicker than before, as the wheels cannot turn as freely.
Inspect the tires on a regular basis -- especially when you suspect a worn out bearing. There will be signs of increased wear and tear on the contact area of the tire, usually indicated by reduced wheel tread. There may also be strain marks, such as cracking, on the tire wall as it tries to take up the slack left by the wheel bearings.
Jack up the car and properly inspect the wheels. Rock the wheel in and out; if there is any play. this is a good indication of bearing damage. In this situation, you could try tightening up the wheel nuts to see if this relieves the problem.
This is also a good time to check if the squeaking was coming from your wheels. Simply spin the wheel and listen.
Remember to jack up the car on all four corners to test all wheel bearings.
If your car is used, it may be worth checking the service history to see when it last underwent a wheel bearing change. Most car manufacturers recommend they are changed every 30,000 miles. If the car has not been serviced for a while, is not used regularly or is coming up to the 30,000 mile mark, the bearings may need to be changed.
