The step in the center of my rear bumper is rusting thru on my 2000 taco. my brother in law has replaced his twice, so this seems to be a taco problem. I see other trucks, not taco's, with rubber or plastic in the step. Is there a after market cover for this? If I buy a new bumper can I prevent this from rusting thru again by putting Por 15 on the back of it or something? Thanks for any help.