Next issue...leaf spring unseated during u-bolt removal...

cannesdo wrote:
So did a nut fall off the center of that place that as holding the leaf springs together -- and after that the u-bolt nuts were doing the job?

No. The head of the center bolt pockets into that block on the axle. It's what indexes the spring and axle into exact position. The nut of that center bolt is still on the bottom, showing through the hole in the center of the plate.