Thanks bro!
My both bumpers are held just by two main brackets, no corner ones left anymore. To mount/unmount I have to go underneath the van to unbolt them and bumpers just sliding out. First pics on page one of this thread basically says it all. Once I finish lowering and have my ride height I want I'll get rid of therm bumpers and make my own lightweight ones from fiberglass.

If it's broken- I'll fix it! If it's not- I'll break it to figure it out how it works so I can fix it.