So my 94 xj has the dreaded rocker panel cancer and I want to replace it with new metal. when I went to order it I saw a rocker panel backing plate. What is the backing plate exactly and do I need it?

 

The backing plate is just like it sounds. It makes up the back side of the pinch seam. When I replaced my rocker panels the backing plate was only shot in certain places so I just got some sheet metal and cut to size and duplicated the bends and welded it to the original backing plate. Once you cut away the rocker you will have a better view of the backing plate and where it mounts too.