When one of the four wheel bearings of the vehicle is damaged, you will hear a continuous buzzing sound in the car while the car is running. It's full of this hum, and it gets louder the faster you go. The following is the judgment method:   
Method 1: Open the car window and listen to whether the sound comes from outside the car;  
Method 2: After increasing the speed (when the humming sound is louder), put the gear in neutral and let the vehicle slide, and observe whether the noise comes from the engine. If the humming sound does not change when sliding in neutral, it is probably a problem with the wheel bearings;  
Method 3: Stop temporarily, get off the car and check whether the temperature of the 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 pad clearance are 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: Raise the car with a lift (release the handbrake and put it in neutral before), and use a jack to lift the wheels one by one when there is no lift, and turn the four wheels quickly by manpower. When encountering a problematic axle, it will send out The sound is completely different from other axles. Using this method, it is easy to tell which axle has the problem.  
 If the hub bearing is seriously damaged, there are cracks, pits or ablation on it, it must be replaced. Apply grease before installing new bearings, and then reassemble them in reverse order. The replaced bearings must rotate flexibly and have no confusion and vibration