A piston and cylinder type damper is provided, with a cylinder (11) having a piston assembly (15) mounted for reciprocal movement therein. The piston assembly (15) divides the cylinder (11) into two separate chambers (12a, 12b), with a restricted flow path (30, 31) for passage therebetween of damping fluid contained within the cylinder. A piston rod (13) is mounted for reciprocal movement with respect to the cylinder (11) and acts via a first one of the chambers (12a) on the piston assembly (15) in a first direction. A seal assembly (17) is provided for sealing between the piston rod (13) and the cylinder (11) in order to retain damping fluid in the first chamber (12a). The seal assembly (17) is movable axially with respect to the cylinder (11), with the cylinder further including a centering device (24) for assisting alignment of the seal assembly (17).