[thenewkid64]

Welcome to the Forum!

The hinge screws have nuts that they tighten into. The nuts are just "back there" they will spin as you describe. The only way to get to the nuts is to cut a hole on the inside to get a wrench on them as someone tightens from the outside. You may want to gob some vulcem on them when you are done.To cover the holes you may need to fashion some sort of trim strip or visit a bone yard for some interior vinyl clad skin to make patches.