This article deals with the design of a technical diagnostics system for hydraulic rotators and the successful implementation of a unique hydraulic test bench. Based on an analysis of the design and function of all types of hydraulic rotators available on the world market, a system of requirements for the test bench and its place in the test centre was formulated. Furthermore, four diagnostic parameters from the group of deformation diagnostics and hydraulic systems diagnostics are proposed and used to evaluate the technical condition of the Indexator IR25 hydraulic rotator. For the evaluation of individual parameter values, a modified Shewhart control chart method is proposed for individual values and moving ranges of each parameter. Based on the measurements of 30 rotators, control limits were designed for statistical evaluation of the technical condition of the mentioned hydraulic rotator.