Abstract: An automatic self-steering trailer axle wherein the wheel spindles are pivotally mounted upon the steering knuckle plate and may be pivoted in front of or behind the kingpin by means of a ratchet wheel which is engaged or disengaged by changing the direction of movement of the axle. The invention also includes a control linkage assembly which may be connected to the trailer axle and also connected to the trailer hitch or towing vehicle steering so that a change in direction of the towing vehicle while it is being operated in a rearward direction is transmitted directly to the control linkage.

Abstract: A release device adapted to be interposed in the air pressure line to an emergency brake actuator of the type which sets its brake by spring action if the pressure in the air pressure line should fail or should fall below a safe pressure; the release device including a main valve movable in response to pressure in the air pressure line to a first position communicating between the air pressure line and the emergency brake actuator; and, in absence of such pressure, is movable to a second position by air pressure from an auxiliary source such as a hand pump or, if needed, air from an available tire, wherein the inlet from the air pressure line is closed and air is supplied from such auxiliary source to the actuator so as to release its brake; the release device further including a bleed valve to insure against any back pressure on the main valve when the air pressure line is functioning.