<div class="htmlview paragraph">Because of performance, installation and maintenance advantages of air disc brakes, they have been used as optional equipment by some of the OEM truck and trailer manufacturers. In addition to the above options, air disc brakes are standard equipment on all Mack Fire Truck Axles. This brake is the result of development and fleet testing combined with experiences from a heavy duty truck air over hydraulic disc brake produced by Kelsey-Hayes since 1975. The most unique feature of the brake is the actuating and automatic adjuster mechanisms integrally sealed in the disc brake caliper housing.</div> <div class="htmlview paragraph">This paper describes the major features of the design and the development during the laboratory and vehicle tests.</div>