This invention relates to apparatus and methods for use in sealing a vascular puncture site and to apparatus and methods for properly locating and deploying a sealing device. The locating apparatus includes a lumen which extends from an opening in the distal region of the apparatus but located proximally of the sealing device, which lumen extends to another opening in the proximal region of the device. When the distal opening is in communication with blood in a blood vessel, blood flow through the lumen and out of the proximal opening signifies such location to the user. When the sealing device is withdrawn such that the sealing device is deployed such that it blocks the blood flow into the distal port, the user will know the location of the sealing device. In a preferred embodiment, the sealing device is then withdrawn proximally a predetermined distance to assure that no part of the sealing device extends into the blood vessel lumen. The sealing device is then detached from the delivery device.
