Abstract: A liquid-cooled heavy duty brake assembly including a number of rotor discs for cooperation with stator discs for braking an external rotating body connected to the rotor discs which is to be selectively braked. The rotors and stators are normally biased apart, but are movable toward each other along the direction of the axis of rotation of the rotor discs in order to effect braking. The casing for the assembly is closed and includes heat exchanging portions around the periphery thereof, including fins extending inwardly toward the axis of rotation of the rotor discs, and the casing is filled to less than capacity with cooling liquid.