The brakes took a couple attempts to get right. The first try used go-cart mechanical calipers, rear left axle mounted disc, and a sheathed steel cable. The cable was attached to a brake handle, a cut down set of bicycle handle bars mounted to shortened forks, and a front bicycle steering tube. It is surprising how far a cable will stretch. The calipers could not be pulled firmly enough to actually stop, or even slow down. Second design replaced the rear mechanical calipers with a hydraulic set. These are actuated by a hand level mounted to the original brake handle. A new disc and the mechanical calipers were moved to the center "collector" shaft. The mechanical calipers are actuated through a solid rod when the brake handle is pulled back.