I know someone that has a late in the year built 98 S'cab, the rear bumper is completely rusted out. To the point I'd be afraid to stand on it. I thought it was from backing into saltwater, a common problem around here, but he has no boat, also he doesn't carry anything corrosive. His frame and axel is fairly rust free. Was there a problem with the bumpers? After I saw his, I took a good look at my 2001 and it has a couple places with very light surface rust, but nothing like his.

 

Get much snow in your area? Salted roads? Washing out the backside of the bumper may help keep it from rotting away. Of the thousands of F150's around here, I've only seen 1 with a rusted bumper and it was just the other day.

 

Not much snow or salt, I saw another truck years ago that looked the same. Was wondering if Ford put out bumpers that weren't coated properly, and if any on else had a problem. I'm not worried about the tiny bit of inside surface rust I have.