I’m a little concerned about jacking on the U-bolt with a bottle jack. Seems like it would be easy for everything to slip and have the axle tube fall onto the jack.
shorty hyd jack The one I have and mentioned in my above reply looks like this one however mine has a 10" X 10" wide base for road side work...IE; truckers special.
....even if the jack slipped from the U bolt and made contact with the axle tube on a std leaf spring suspension, it will not hurt/bend/dent/crush/other rv website theories, the axle tube. Its simply to thick for that to happen.
Drop by a local big rig trailer repair shop and watch them bend axle tubes by placing some type of jack under it in a specific place and then apply tones of hyd pressure to bend the axle back into proper alignment (toe +/- and camber)
