Abstract: The present automatic clearance adjuster mechanism maintains a predetermined maximum brake clearance regardless of the wear condition of the brake. The brake includes a longitudinally extending rod mounted to the brake housing external to the piston element. The present automatic clearance adjuster mechanism includes a sleeve element disposed about the rod, and a biasing element disposed for releasably holding the sleeve element against the rod for preventing movement thereof along the rod to limit the retraction of the piston element to a predetermined distance relative to the sleeve element.