Abstract: A brake actuator has a housing (4) containing a pair of brake-applying members (9, 10) interengaged by way of a threaded connection (11) to form a strut of which the length is variable by rotation of one of the members. One (9) of the members has a gear formation (16) thereon meshing with a corresponding formation (22) on a drive gear (21). The formation (22) has an extended profile permitting simultaneous rotational and translational movements of the member (9) relative to the drive gear (21) so that rotation of the drive gear causes expansion and contraction of the strut for brake actuation. The brake actuator housing (4) is mounted at a location adjacent the wheel while a power unit (10) is carried by a suspension member (1) in order to decrease noise and vibration transmition.