Bearing of the four wheels, it has no rubber sleeve wrapped grease, usually need to add lubricating oil? - bearing knowledge

The car can all rotating parts can have lubrication, or wear quickly. Have a plenty of liquid lubricants, need to be replaced regularly, have a plenty of lubricating grease, do not need to change. Such as half shaft of ball cage, steering machine outside the tie rod ball head, lubricating grease, as long as the package of these oil rubber sleeve not damaged and make the oil leak, is life do not need to change. If a bumper damage, grease and glue set to change, because it is not in grease can be left out, grease can lack eventually lead to bad lubrication. Today we would say four wheels bearing, it has no rubber sleeve wrapped grease, usually need to add lubricating oil? Buses trucks the usual maintenance have to add grease all moving parts of the project, has the special add mouth, with a grease gun can directly into it. Car is not to need to do the maintenance, the wheel bearing is used lubricating grease lubrication, but it is the overall structure of the seal. The bearing is closed, the inside of the lubricating oil will not flow to outside and goes into the dirt inside to outside. As long as the grease flow not to come out, it would not loss, its role is only a simple and smooth, there is no failure doesn't work. So four wheels at ordinary times is not to need to add lubricating oil, as long as no abnormalities, life does not need maintenance. Although don't need to do maintenance, but also has bad. The performance of the wheel bearing is broken is there is sound, usually buzzing noise. Because of lost the ball inside the circle or have abnormal wear and rotates with the friction and noise. Bearing as long as there is a sound, can't repair, only replacement. Different models bearing is different also, have a plenty of a monolithic, together with the shaft head, abs sensor, broken will be replaced at the same time, the price is very high. There is a common small bearing, replace this widget can only when replacement, price is very cheap, but more troublesome, to change partners than in integral. Wheel bearing life span of the average car is very long, most can be used more than ten kilometers, some car ran hundreds of thousands of kilometers, life is not bad, usually encountered in bearing most of them are the old car. Bearing does not need maintenance, so its life besides itself quality problem, also had a lot to do with vehicles using the environment. Bad roads, road is more, always don't slow down a rutted road speed, vehicle load is large, often full or overload and so on, will affect the bearing of life. This several kinds of road conditions and method of use, will not only affect the service life of bearing, the suspension, the service life of tires and other chassis parts have influence, so the slow place must slow down, don't overload.