The hydraulic pump is an important element of the hydraulic system, with its help, the working fluid is pumped into the hydraulic lines. In case of hydraulic pump malfunctions, air, as well as foreign impurities, can enter the working fluid, causing it to overheat. Overheating of the working fluid provokes the earliest wear of the hydraulic motor parts. The energy of the working fluid flow, pumped by the hydraulic pump, is converted by the hydraulic motor into the energy of shaft rotation. The serviceability of the hydraulic motor should be given special attention.