The paper shows the need of using the condition based maintenance of belt conveyor driving systems to monitor their condition for presenting vibro–acoustic severity and preventing its effect development by replacing the rolling elements bearings, which are characterized by increased over limit backlash. It is shown that the vibro–acoustic (vibration and noise) effect/result given by a belt conveyor driving system depends of their condition. The condition of belt conveyor driving systems are the result of several factors that can be divided into four groups namely; design, production technology, operation, change o condition. The influence of mentioned four groups of factors on the vibro– acoustic severity is considered in the paper. The consideration leads to conclusion that suitable vibration parameters should be evaluate which shows the increase of a backlash in rolling elements bearings. The parameters are characterised by a load–yielding characteristic that gives relation a vibration diagnostic parameter as the function of load or function of RPM. These two characteristics are equivalently positively and negatively correlated. That means that if the load increase the vibration parameter also increase but if RPM increase the vibration parameter decrease.