Abstract: A prop assembly for vehicle doors hung from the top and adapted to swing upwardly and outwardly, in which the prop assembly has a cylinder with an axial reciprocating rod connected to the door and to the door frame along the side thereof, and a spring in the cylinder urging the rod outwardly through the end of the cylinder to open the door and hold the door in open position. A fixture is pivotally connected to the end of the cylinder and another fixture is connected to the outer end of the rod, the latter fixture being secured to the door and the other fixture to the door frame. One of the fixtures consists of a base plate having an upstanding stem pivotally connected thereto for rotation on the base plate as the door is opened and closed.