An isolator comprising a shaft (10), a pulley (20) journalled to the shaft on a first bushing (40) and a second bushing (50), the shaft comprising a shaft stop (12) disposed on a shaft radially outer surface (14), the pulley and the shaft rotationally moveable relative to each other, the pulley comprising an inner hub (23), the inner hub having a pulley stop (24) disposed to cooperatively engage the shaft stop, a torsion spring (30) engaged with the shaft and the pulley, the torsion spring exerting a contractive force parallel to an axis of rotation (A-A) in order to retain the pulley on the shaft, a cover member (60) fixed to the shaft, the pulley urged into engagement with the cover member by the torsion spring axial contractive force, and a rubber member (80) disposed on the shaft stop for engaging the pulley stop.