The floating-caliper disc brake on the front axle of heavy trucks and busses, should enable the heat to be more quickly emmited into the open air than by the drum brake. Apart from that, it prevents one-sided braking more reliably and it makes brake-pad replacement easier.
A compressed-air membrane cylinder operates two pistons, either through a lever-system (picture below) or directly (picture above), which press a brake-lining against the brake disc. The brake caliper is shifted through the opposing force, bringing the outside lining into contact. In order that the brake caliper may be shifted sideways, it is floatingly mounted on a spindle assembly carrier made of spheriodal cast iron.