An automatic slack adjuster includes a lever configured to be coupled to a push rod of a brake actuator, and to pivot about a rotational axis when actuated by the push rod, the rotational axis having a predetermined fixed location relative to the vehicle. A stroke indicator label is arranged on the lever and configured to designate, for the automatic slack adjuster, a predetermined zero stroke position, a working stroke range, and an overstroke range. A stroke indicator element is configured to visualize the current stroke level of the automatic slack adjuster on the indicator label by way of relative movement between the stroke indicator element and the stroke indicator label in response to pivotal movement of the lever. A mounting bracket of a mounting interface can be adjusted relative to the rotational axis for correctly installing the stroke indicator element.