a bit of axial play and is able to slide. If this is not the case, work on the locknut located in the rear part of the hexagonal rod until you obtain this condition. If the internal sensor does not slide well through its stroke, check - the play of the upper roller (H, Fig.5) on the external hexagonal rod. If necessary, loosen the fixing nut on the upper roller (I, Fig.5) and turn the eccentric pin (L, Fig.5) to modify the roller play on the rod. With the sensor in its resting position, this play must be minimal so that its action is effective throughout its stroke. If the internal sensor lever is removed, check: - In the service environment with the lever in the rest position or with the pin located on the lever inside its plastic seat, that the status of the diameter micro-switch is “ON”. If this is not the case, change the position of the sensor lever with respect to the internal hexagonal rod on which it is fit until the status of the micro-switch is correct as indicated previously.