Abstract: An expanding bush and captive bolt assembly (1), comprising a bolt (2), a generally cylindrical bush (4), and a ring clip (6) that retains the bush on the bolt. The bush (2) has an inner surface with a portion (22) that has a frustoconical taper, a channel (12) that extends circumferentially inside the bush, and an expansion split or slot (7) so that the bush may be expanded radially. The bolt (2) has a threaded portion (10) for engaging with a socket that has a matching thread, a head (8) by which the bolt may be rotated to tighten the bolt (2) to the socket and to squeeze axially the bush (4), a shaft (18,20,23) between the head (8) and the threaded portion (10), said shaft having a portion (20) with a taper that engages with the tapering portion (22) of the bush to expand the bush (4) as it is squeezed axially between the taper (20) and the socket, and a channel (16) that extends circumferentially around the shaft and which opposes the channel (12) of the bush.