A coupling system for receiving a push rod includes a housing defining an internal channel having a sloped wall, and a piston received within the internal channel. The piston includes at least one flexible member arranged within the channel to be acted upon by the sloped wall to engage the push rod. The only external force required to couple the push rod is an axial force on the piston in a direction. The only external force required to de-couple the push rod is an axial force on the piston in an opposite direction.
