For some reason the entire rear bumper on my car rattles when I knock it with the palm of my hand. Like it has bolts that have started to come undone or something. But everything looks like it's in order, the sides are around the studs correctly, it's riveted underneath at the base of the spare wheel, and I think I can hear it when I go over sharp bumps.
Anyone else have this happening to them?

Could be the bolts in the chassis rail have worked loose. If everything else seems secure, perhaps it's where the bar mounts on to the reo.
cheers, Bob