ok so I put one of the warn tire carrier bumpers on a couple weeks ago.. Now I don't have the tire carrier yet, but the part that the tire carrier mounts to is already getting rusty....I have sprayed wd-40 on it and scrubbed it with a rough sponge and that helped for a day or two, but then it rusts back up??? whats the deal, I thought it was supposed to be rustproof??? will this cause any problems??