Abstract: A fully lined disk brake adapted for use to advantage with a wheel of a light-weight passenger car has a radially outwardly open brake housing secured to a hub of the wheel by circumferentially spaced radial arms. The brake housing has a radially inward wall provided with spaced openings which communicate with openings between the radial arms which support the housing. A stepped ring responsive to fluid under pressure is disposed between the brake disks in the brake housing for actuation of the brakes. The stepped rings which form the brake actuating member are provided with axial projections having spaces therebetween which contact the brake shoes. Air for ventilating the brakes is drawn through the openings between the arms and in the inner wall of the housing and passes between the projection members on the stepped rings to ventilate the brake disk.