A process for testing the quality, in particular the stiffness and the phase, of an elastic joint for connecting two other parts while filtering vibrations transmitted between these two other parts, said elastic joint being meant to work in axial, radial or torsional direction, disposing or not disposing of one or more hydro-elastic chambers and of two cylindrical concentric support elements, the inner support element being located to a large extend inside the volume defined by the outer support element, the two support elements being connected by a set of components made of rubber or elastomer or, if applicable, of plastic and metallic parts, wherein said support elements are themselves respectively attached to the two other parts which the elastic joint connects, wherein a technique of testing by impact is applied within the timing of the production line of the elastic joint, i.e. less than 10 seconds per cycle, for identifying good joints from bad ones through a frequential analysis of the oscillation of the impacted area of the elastic joint, characterized in that the values of the phase shift of the frequential analysis are compared with a bandwidth of permissible phase shift.