You don't need to remove the nut. Just pull the rod out of the opposite side. There is a keeper ring that has to be removed, just remove the large snap ring from in front of the gland, then tap the gland in a little to remove the keeper ring. Tap the rod and gland out from the side that has the nut you are considering taking off. Then after rod is out you can install the wiper and internal seal with the barrel still attached to the axle. The only reason for pulling the barrel, if you can get it off, would be for honing purposes. I haven't seen any that need to be honed though!