Areas that rust - Rear chassis

Rear chassis leg capping plate (bottom filler plate of box section)

The capping plates on the main rear chassis sections are on the bottom, the formed sections being quite heavy top-hats with a thinner filler spot-welded across the flanges underneath (these chassis legs are cantilevered and stepped-up aft of the main floor chassis members, as they exit behind the rear cross-member)/

If water continually gets into these sections, the capping plate will eventually rust, the water can also get trapped betweeb the flanges and the spot-welds.

One way that water can get in there can be seen here Snorkel box, through the o/s snorkel box (on 2.1 Syncros, anyway) behind the o/s tail-light. (Drilling a 1/4" bang in the middle of the snorkel box floor, where the pressed fingers cross, can alleviate most of the problem I imagine. Deburr & swage it downwards a bit; helps stop water penetrating from below as well as draining properly.