its outlet ports 15 the direction of rotation of the electric motor 12 is reversed by its remote power source 18 causing the direction of water expulsion and the direction of travel of the vehicle to be reversed the power source 18 is conveniently equipped with a timer which causes the reversal and the timer is conveniently set to the time it takes the vehicle to traverse a length or width of the surface being cleaned thus as the vehicle reaches an end of this surface the timer of the power source 18 acts to reverse its general direction of travel when the steering ribbon 50 is locked in a position such that it occludes a portion of one of the slots 90 it causes the back axle 80 to become tilted when the vehicle moves forward and this alters the direction of travel of the vehicle in this way the vehicle traces a pattern that covers the entire surface to be cleaned rather than moving back and forth over the same path referring to fig8 the bottom of the chassis 20 of the vehicle 10 is provided with inlet ports 22 which have side walls 24 and back walls 26 as well as flap valves 28 in one embodiment side walls 24 and back walls 26 extend from the.