An apparatus for sealing a puncture includes a positioning member including a proximal end, a distal end sized for insertion into a puncture, an expandable element on the distal end, and a tension indicator on the proximal end. The tension indicator includes a distal housing portion fixed relative to the proximal end, and a proximal housing portion or handle movable proximally relative to the distal housing portion. The handle is biased towards the distal housing portion such that, when sufficient tensile force is applied between the expandable element and the handle, the handle moves away from the distal housing portion. During use, the distal end is introduced through a puncture into a vessel, the expandable element is expanded, and the positioning member is partially withdrawn until the expanded element contacts a wall of the vessel and the handle separates from the distal housing portion, indicating that sufficient tension is applied.