Connecting assembly comprising a housing component (14), a stop ring (22) consisting of two half-rings (22A, 22B), and a length of shaft (12). Axial end stops (25) formed on the length of shaft prevent the ring from moving axially along the length of shaft. The connecting assembly comprises retaining means (34A, 34B) able, when the ring is placed in a mounted position around the length of shaft and held axially by the axial end stops, to prevent respective first ends of the half-rings from moving apart. In the mounted position, the ring prevents relative movement in an axial direction (X) of the length of shaft (12) with respect to the housing component (14). It is therefore interposed between the length of shaft (12) and the housing component (14) and is held radially against the length of shaft (12) by the housing component (14). The invention also relates to a method of mounting such a connecting assembly.