No, it's too thin to tap, and the cap does have a function even if the design is stupid. By that I mean the cap seals with an o-ring but cannot reasonably be opened to service the o-ring, without distorting the 4 little tabs enough to permanently destroy a good seal. Actually, this would be OK if you could just buy a replacement cap to replace along with the o-ring.How thick are the tube walls at the damper? can you tap the opening and put a bolt or cap nut in/on there? (with some thread sealer or epoxy)
It would be easy to just remove the cap and plug the hole, but that doesn't seem like a good idea. If I were to do anything along these lines, I would surround the entire cap with epoxy right down to the rail. I picture using an old film container, with the bottom cut off and the plastic sleeve slipped over the cap, as a mold to hold the epoxy while it hardens.
I'm honored. I'm using a cable tie to hold the cap down. I used it to hold the cap in place while my JBWeld hardened, and saw no reason to remove it.The true ******* way of fixing it would be to put a hose clamp around the rail over the cap
I found a source to get the rail delivered to me by expedited shipping for less than $70, so I ordered it. Fuel tank repair epoxy sounds like a workable solution but the kits cost at least about $10 and I think I'd need 2 of them to have enough material. Add in all the work to clean and prepare the surfaces, and it just seems more practical to replace the rail entirely.