Abstract: A coupling includes a male half and a female half, where the female half has a fitting rigidly fixed to a stationary member such as an agricultural tractor. The male half can be coupled within the female half. When the male and female halves are coupled together, a valve assembly in the female half allows fluid flow through the coupling. When the male half is pulled out of the female half, the male half automatically disconnects from the female half. When the male half is removed, the valve assembly closes to prevent fluid flow through the coupling. The male half also automatically disconnects when the fluid pressure in the fluid system increases above a predetermined amount. In either case, a coupler body within the fitting moves against a centering spring to allow the male half to be removed from the female half. The selection of an appropriate centering spring determines the breakaway and overpressure release force.