Abstract: An adjustment arrangement for a hydraulic brake actuator (11) of the type having a piston (17) which moves a preferred distance within a cylindrical bushing (15) portion of a housing between a quiescent retracted position with a preferred clearance space between one piston end and a brake mechanism, and an extended position with the piston end engaging and actuating the brake mechanism in response to the application of hydraulic fluid pressure includes a return spring (23) which, upon relief of the hydraulic pressure, urges the piston (17) back from the brake mechanism engaging position to the retracted position. There is an internally disposed mechanical piston clearance space adjustment feature including an expandable sleeve (33) which surrounds a cantilevered pin (37) having a split expander ring (35a, 35b) near a free end thereof. Upon excessive piston (17) travel, the sleeve moves along the expander ring (35a, 35b) to establish a new retracted piston position.