The early Z's used a simple vinyl covering on the A-pillars, but in 77 they switched to a screw retained plastic trim A-pillar cover. Well Datsun must have messed up some dimension somewhere because the plastic trim covers often crack due to the stress of tightening the screws. On my right hand side, I had one of the screws pull through. Cracked the plastic mounting hole clean off.
My first attempt to remedy the situation was to simply buy another used pair somewhere off some forum. Unfortunately, the donor pair I bought not only had the same problem, but it was even the same screw, same location. This meant that I couldn't even use one side from my original pair, and the other side from the donor pair. It became clear that this is a common problem and it's not just me. With that in mind, I took matters into my own hands.
Here's what I started with. My right side. Completely cracked off mounting hole in the lower position:
It's supposed to look like this. Here's the other side where the screw boss is still intact:
Figuring I had nothing to lose, I put a piece of tape over the hole on the visible side:
Crosshatched the plastic on the hidden side:
Taped a short length of small diameter cardboard tube where the mounting boss should be and filled the moat with epoxy:
Gave it a day to cure, peeled off the cardboard, and using a dremel and some hand filing, I contoured the new boss to fit the into place on the car and drilled the hole for the screw:
Countersink the other side for the screw head:
Used a small brush to paint the exposed epoxy:
And after the paint dried, the repair is nearly invisible:
So I also figured that since I'd already seen two broken bosses, I would take the opportunity to reinforce the remaining ones which had not broken off (yet). I crosshatched the area and blobbed on a generous amount of epoxy to support the posts. And while I was looking at everything, I also noticed a couple small cracks starting to form along the edges, so I made a couple metal splints and epoxied them into place as reinforcement.
After all this work, these things should be good for another forty years. Here's one of the splints next to a reinforced mounting boss:
Installed back in the car, and I know it's the little things, but I don't have to look over at the right side of the car and see that missing screw in the cracked off mounting boss! Happy Happy!