The new maintenance system of semi-trailer combination as a most used road freight transport means is the subject of interest in this article. The real experiences from practice and creation of the FMEA analysis of the system using software support are the basis of wear and damage analysis of air brake system components used on the semi-trailer combination. The desire to improve market position of the company, customer satisfaction, but also the product specifications, government regulatory requirements, agency recommendations, and legal implications are the grounds for continuous improvement of the product quality, reliability and safety. These reasons push the product manufacturers to perform risk analyses, which helps them identify and minimize system failures during the life cycle of product. One of the risk analysis techniques recommended by international standards to identify possible failure causes is the FMEA methodology. It helps to locate the failures and reduce their consequences, so that the intended function of the machine is fulfilled. In this paper was presented the wear and damage analysis of individual components of air brake system and creating of the FMECA analysis for semi-trailer combination. Base on them, new methods to detect failures of components of air systems, preventive measures and set up of a new planned preventive maintenance system for air brakes was designed. The cost of the proposed maintenance system is 2.2 times higher than the cost of the current maintenance system, but it minimizes the failures and their consequences (traffic accidents).