Abstract: A brake actuator includes a tubular housing member, connected at a first end to a cylindrical housing with a member for admitting fluid, a piston with a sealing member mounted for reciprocal movement within such cylindrical housing, a tubular stem connected at one end to such piston, the tubular stem having a first conical surface at its other end, a piston return disposed intermediate such first piston and the tubular housing, a flange connected at one end to another end of the tubular housing, a pair of abutment surfaces carried by such flange and an externally threaded rod having a first portion extending inside the tubular housing and such tubular stem and a second portion extending outwardly from such tubular housing and through the flange, the improvement of a collet style slack adjuster to adjust for wear of braking elements.