When one of the four wheel hub bearings of the vehicle is damaged, you will hear a continuous buzzing sound in the car when the car is driving. It is not clear where the sound is coming from. It feels like the whole car is Full of this buzzing sound, and the faster the speed, the louder the sound. Here is how to judge:   
Method 1: Open the car window and check whether the sound is coming from outside the car;   
Method 2: After increasing the vehicle speed (when the hum is louder), put the gear position in neutral and let the vehicle coast, and observe whether the noise comes from the engine. If the hum does not change when coasting in neutral, it is probably a wheel bearing problem;   
Method 3: Stop temporarily, get out of the car and check whether the temperature of the wheel axle is normal. The method is: touch the four wheel hubs with your hands, and roughly feel whether their temperatures are the same (when the brake shoe and disc gap is normal, the temperature of the front and rear wheels is If there is a gap, the front wheel should be higher), if you feel the difference is not big, you can continue to drive slowly to the maintenance station;   
Method 4: Use a lift to lift the car (release the handbrake and put in neutral before). When there is no lift, you can use a jack to lift the wheels one by one. Manually rotate the four wheels quickly. When a problematic axle is encountered, it will emit The sound is completely different from other axles. With this method, it is easy to distinguish which axle has the problem.  
 If there are cracks, pitting or ablation on the hub bearing when it is severely damaged, it must be replaced. Before installing the new bearing, apply grease first, and then install it in the reverse order. The replaced bearing must be flexible and free of miscellaneous and vibration.