Abstract: In a combination including a towing vehicle equipped with a ball type tow hitch and a trailer equipped with a forwardly projecting tongue portion having a socket type tow hitch mounted on its forward end removably universally coupled to the ball type tow hitch the free ends of a U-shaped frame are pivotally supported to the rear of the tow vehicle for oscillation about a horizontal transverse axis and with the frame opening in a horizontal direction and having its closed end spaced rearward of the ball-and-socket type tow hitches and underlying the tongue portion of the trailer. An adjustable caliper-type friction brake assembly provided with opposing and relatively adjustable generally horizontal and vertically spaced friction surfaces is stationarily supported from the tongue portion of the trailer with the closed end of the U-shaped frame disposed between the friction surfaces of the brake assembly.