A system for checking the axial position of a bearing (30) inside an hole (31) of an E-block (29), preferably during the assembly of an HSA, comprises a reference system (3) that locates the E-block, a coupling element (17) that comes into contact with the bearing, a floating element (8) that, being connected to the coupling element, assumes the attitude of the bearing, two or more detection devices, for example optoelectronic, that cooperate with the floating element and detect at the same time, at checking areas spaced apart from each other, quantities indicative of the position and, in case, of the attitude of the bearing with respect to the E-block, and a processing unit (50) for receiving and processing the detected quantities. A corresponding method for checking comprises the steps of locating E-block and bearing to mutually movable parts of the reference system, detecting at the same time, at least at two checking areas spaced apart from each other, quantities indicative of the position and, in case, of the attitude of the bearing with respect to the E-block, and processing the detected quantities. The invention relates also to an equipment and a method for assembling HSAs, that respectively employ the above-mentioned system and method for checking the mutual position and, in case, the attitude of the bearing with respect to the E-block.