Abstract: The invention pertains to the fluid powered brake systems of vehicles using brake drum and lined brake shoes internally expanded by cam. The invented device automatically adjusts the slack, which develops due to the wearing of brake liners and the drum. The device is depicted in FIG. 1 when the angular movement of the Lever Housing (1) exceeds the desired limit due to the wear, the internal device adjusts the excess clearance of slack automatically. The parts consist of Worm Wheel (3); an enmeshing Worm Shaft (4); a Paul (6); a Leaf Spring (1); a Ratchet cylinder (5); an Acuator Rod (7); a Guide (9); an End Connector (8); a Clevis (2); and Clevis Pins (2A) and 2(B). When brakes are applied the Actuator Rod (7) gets pulled out and brings the Paul (6) in engagement with Ratchet cylinder (5). On the return stroke the Paul (4) rotates the worm shaft (4) which in turn rotates the worm wheel (3) and the attached cam thereby removing the slack.