I have started to work on my tailgate. I have decided to remove the inner panel because: it is very beat up; It is easier to replace than the outer panel; And I can put some liquid wrench on the hinge bolt threads, inside. Once the inner panel is off I will address any rust inside the tailgate, then deal with any issues on the outer panel, from both sides. Here are a couple of pics and I will post more as I progress..
I assume the holes in the tailgate are from a pioneer tool rack, and license plate. The inside of the tailgate was not terrible… It is still quite solid. I will replace the bottom few inches of the outer skin, and the entire inner panel with new metal, of the correct gauge.
There was much more damage to the outer panel than I wanted to deal with, and approximately the same amount of work to replace a large section as a small one. I sandblasted the frame and chemically treated the surface to neutralize any rust. The light gray areas are all bare metal.
It is relatively easy to re-skin, but the compound curve on the top edge is tricky. You have to experiment to get the top edge right, after which the rest of it goes on no problem.
Gordon, in Scotland
( Now officially given up on any form of politics )
I ended up removing the upper outer skin to deal with a stubborn dent, and this let me clean/treat the interior. The upper piece will be reused and new metal welded below.
I reinstalled the upper outer panel by plug welding the top edge, where I had drilled out the spot welds. I then attached a new 18 ga. panel as the lower outer panel. I used 3M body panel adhesive around the edge, and tack welded the two edges together. I will complete the welding from the inside to reduce the amount of grinding on the exterior weld. Panel adhesive is incredibly strong, seals the entire seam, and protects against corrosion. You can see the black adhesive between the frame and panel; total surface contact.