to add to it, sounds like you are replacing the seal maybe. anyway, that nut is technically one time use only, if you take it off, it is recomended to replace it. the way i do it everytime is to use blue thread locker, and reuse the original nut. i have seen a couple times where someone reused the nut, and didn't use any threadlocker, and the nut did loosen up. i've never had a problem with locktite, or new nut.