I can’t tell how bad that is. Is that paint and rust flaking off? Or is it rusted all the way though? If all the way through, then it probably trapped water on the inside and rusted out the bottom. Remove all paint and flaking rust as that traps salt and water.
Even if it is rusted through on the bottom, it’s still probably stronger than a new frame on the previous generation F150 which had the worst IIHS crash test score. Those had square tube frame in the front part of the truck. That part would rust on the inside and the bottom of the frame would get smashed when they put it up on a lift at a shop. If trapped water inside did this, then only the bottom part of the frame is bad. Looks like you could buy a strip of steel and just cut out the bad part of the frame, even if it makes the frame smaller. Then just weld the strip in.
I just realized that this thread is old. I wish there was a feature like “Don’t bump this thread to the top”. Somebody submit a feature request for this! It’s useful for people coming in from search engine results or the original poster, but it doesn’t need to be bumped to the top for everybody to resume discussing it.
