The paper describes and analyzes a newly developed brake mechanism supplied with an integrated automatic slack adjuster for heavy vehicles. The device is based on the crank mechanism principle. The geometric properties are examined and it is shown how some design parameters can be adjusted to meet specific requirements. The relation between applied torque and the brake torque is derived and in an example an inherent brake amplification property of the mechanism is shown. This property persists even when friction in the mechanism is considered. The automatic adjusting system is travel sensing, so the relation between the travel of the sensing device and the clearance is analyzed. Finally, the amount of correction of the clearance is treated and it is shown how the prescribed clearance can be maintained within very narrow limits.