baler velt tracking vermeer 5410

So put all new velts on baler, vermeer 5410. They looked good before baling baled a coupke bakes ok . Than start tracking off the left . Found a roller on top skewed a little . Adjusted that and everything looked 12 bales later I Increased density a litte and a few bakes laterall belts are tracking way off to the left again . Never had any tracking problem before. Any suggwstions ? Thanks