The problem may be that the 1/2 inch drive sockets are too small to fit the seal and you may not have a 3/4 drive socket set to get a socket.
You could use an old mower blade plate hub if you have one or cut a round plate out of 1/4 inch steel ,if you can't find a bit of metal cut a piece of wood to put on the seal then hit the wood with a hammer.
