Yes this happens - it happened to me years ago on my original '85. My fix
wasn't quite as elegant as Johns. I just found some stainless bolts and
nuts that would fit in the existing hole and fastened it on that way - it
was years ago so I don't recall how easy it is to get to that spot on the
underside of the van. Then I just caulked the holes underneath to prevent
water and such from getting in further.
Thanks,

Jeff
'85 GL (Gertie)
'78 Bus (Melissa)