Abstract: The brake adjustment monitor has a pull or breakaway switch having an activation pin as part thereof which activation pin is attached to the push rod and slack adjustment arm assembly of an air brake system by a cable. The switch itself is attached to an existing bolt screw or like attachment device on the air chamber assembly of the brake. When the switch and cable are installed on a brake assembly the cable is adjusted to a length to pull the activation pin to operate the switch when the push rod has traveled a predetermined distance. This distance, as is known in the art, is an indication of brake wear or misadjustment. A number of bulb indicators with or without sound indicators may be mounted on a trailer or motorized vehicle and electrical connected to indicate to an operator the switch activation.