I had the passenger seat from my 81 242 out last weekend for preventative maintenence / slight restoration.

I remember someone recently asking about the seat back tilting to one side, and didn't see this on the list of possible explanations. I don't know if this would apply to the 4 and 5 door seat frames, but I was missing 2 out of 3 bolts on the left, and one on the right. Simple to replace, and now the chair is much sturdier- without them you could really shake the whole frame. There is of course, added comfort, which is also due to a home made lumbar revamp and patched seat bottom.

In the picture below I circled the holes where 2 bolts were missing. I replaced them with 5/16, 1 inch long.