I had a similar prob. with my 88 300. Even after I replaced the seals, I got a small amount of residue around the center or the wheel. Just be careful not to over tighten the bearing retaining nut when you reassemble. Tignten gradually until you get no play in the wheel, then back off one space on the retaining cup that fits over the nut, check for play again, if OK put in the cotter pin.