A dolly apparatus for use on an assembly line includes a base frame. A swing out arm is rotatably connected to the base frame by a pivot linkage. An automatic arm closing assembly moves the swing out arm from an installation position to an initial position. The automatic arm closing assembly includes an engagement member located laterally outside the base frame. A swinging linkage is rotatably connected to the base frame. A support rod connects the engagement member to the swinging linkage. A connector rod connects the swinging linkage to the pivot linkage. The engagement member has a retracted position and an extended position. The connector rod moves with rotation of the swinging linkage and rotates the pivot linkage thereby moving the swing out arm from the installation position to the initial position with movement of the engagement member from the extended position to the retracted position.