Body /frame bolts.
I had removed the frame from the body last week, gave it a good inspection and all is good, so I completely sprayed the frame with rock guard and place new foam on the frame where the body sits on plus she is getting brand new bolts. All 6 bolts that bolt the body to the frame we very rust and very thin. as they were rotted, good thing the didn't snap and the body flew off the frame.
It is a good idea to replace them after 40 years I would think.