You will have to replace the whole
axle, the original is not made to adapt
brakes to it. I've heard of one owner that machined out new
axle stubs and adapters to put brakes on his
Uhaul 13, but he has the machinery and knowledge to do that. If you do end up buying it, there is a good
Uhaul group on Facebook now where there is a lot of good information available. In the document center here there is also good info on the
Uhaul campers.