Closed-loop type disc brake

An hydraulically-operated disc brake for a vehicle comprising a rotatable disc, friction pad assemblies for engagement with opposite faces of said disc, an hydraulic actuator for applying said friction pad assemblies to said disc located on one side of said disc, said hydraulic actuator comprising a stationary housing incorporating spaced arms projecting towards said disc, and first and second oppositely acting pistons movable relative to said housing, said second piston being of an axial length substantially equal to that of said housing, a yoke straddling a portion of the periphery of said disc and fitting loosely over said housing and said arms, said yoke being movable with respect to said housing in a direction parallel with the axis of said disc, one of said friction pad assemblies hereinafter referred to as "a directly actuated friction pad assembly" being applied directly to said disc by said first piston and the other friction pad assembly hereinafter referred to as "an indirectly actuated friction pad assembly" being applied to said disc by said second piston which acts on said indirectly actuated friction pad assembly through said yoke, a rigid connection between said yoke and said second piston constructed and arranged so that the drag on said indirectly actuated friction pad assembly is transmitted to said housing only through said second piston, flexible sealing boots connected between said housing and each piston, and said directly actuated friction pad assembly being guided for movement with respect to said disc between said arms which take the drag on said directly actuated friction pad when the brake is applied so that the drag on said indirectly actuated pad assembly is taken by said housing through said second piston independently of said arms.