dont take the chance buy new ones they dont cost that much. as for the grease in the drum , always install new seals and pack the bearings with a good high temp wheel bearing grease. and make sure the seal is seated proplery and not bent. some seals have a spring on the inside make sure if yours does have one that it dont come off as you install it, and of corse make sure it fits the spindel where it rides and that the spindel is not rough. I have been given the wrong seal many times