I recently did this. My problem was the molded insert in the latch had deteriorated. I searched and could not find a replacement insert and got a good used set-cold climate seller-of rear latches in EBay.
Climb in the rear hatch with a soft sweater. Loosen one side 2 10mm nuts. Grab latch and slightly twist while your shoulder gently lifts the hatch. When you do not feel a pinch on the hatch pin, tighten nuts. Note: on both of my cars the inner latch side is twisted in further than the outer. YMMV
GL
John_AZ
1988 924S + 1987 924S