A ball ramp brake including a housing, a disc assembly within the housing, and an annular rotatable actuator to actuate the brake by compressing the disc assembly. The rotatable actuator includes a plurality of depressions oriented circumferentially therein which become progressively shallower in a first circumferential direction. A plurality of depressions are circumferentially oriented in a surface of the housing and become progressively shallower in a second circumferential direction. The depressions in the actuator and the depressions in the housing each have a first angle of depression that is steeper than a second angle of depression. A boot seal may be provided between the fluid chamber of an actuating cylinder and the inner area within the housing to prevent fluid leakage. In addition, a cooling chamber may be provided in the housing to improve the brakes efficiency.