I am working on the running boards for my 1940 1/2 ton. I have two small spots that have rusted through the running board and the support channel that runs down the middle of the running board.
I have cut out the offending metal and removed a section of the support channel. What greeted me under the channel is a considerable amount of rust.
I am wondering what people do to get some kind of rust prevention (paint or whatever) into areas that are hard to reach like this one. There seem to be other places like the roll on the top of the bed sides too.
Once these channels are welded on getting anything but water

into them seems pretty difficult.
Thanks