One problem related to frame rust has been reported for the 1997 Ford Ranger. The most recently reported issues are listed below.
I bought this truck in ohio in October 2014, after purchasing I noticed quite a bit of rust eroding the frame behind 20" low profile tires, I put factory suggested tires on it the leaf spring hangers broke in early Dec. 2014 after that was fixed, the erosion was noticeable. Now the shock has fallen off and the frame has a crack through it at the leaf spring hanger. The truck is not drivable at this point. I need another frame or will have to junk the truck.