Seem some evidence so need to investigate and sort out.
On SOB's (barn doors) there's a big long stainless steel strip secured over the top of the rubber seal that runs all the way around the opening on the body. 58574-60010 is the p/n for it described as 'plate rear floor mat support'.
I replaced that seal probably 8 yrs ago. I don't know if tailgate 80's have the strip, but on barn door ones it creates a water trap.
The big seal is quite a funky thing, but splits apart in the middle at the bottom as the rubber shrinks with age.
On SOB's (barn doors) there's a big long stainless steel strip secured over the top of the rubber seal that runs all the way around the opening on the body. 58574-60010 is the p/n for it described as 'plate rear floor mat support'.
I replaced that seal probably 8 yrs ago. I don't know if tailgate 80's have the strip, but on barn door ones it creates a water trap.
The big seal is quite a funky thing, but splits apart in the middle at the bottom as the rubber shrinks with age.