I typically fill the shock from the bottom up to the threads. Then, I start screwing in the bottom insert with the shaft pulled all the way out. Before the insert is all the way in I would push the shaft about 3/4 of the way in to bleed out any excess. Then, I would finish screwing in the insert. After the insert is screwed in and the shock is sealed I would test the full range of the shock motion. Make sure you don't feel any air and also make sure that when the shaft is completely pushed in that it doesn't hydro lock and spring back forcefully.