Hey Andy, thanks for the questions. Those internal coil springs are holding up well (based on my personal experience) as they do not have to exert much force to eject the articulated member and J-Hook (only needs to pop out the whole assembly maybe 6-12"). I experimented with various springs before I came across the final version. Plus I've got the internals lubricated w white lithium grease to help in the ejection (which somewhat addresses the corrosion issue). Moisture intrusion, and dirt, are part of the game, but with the tailgate closed there is only maybe an 1/8" gap between the bedside and the tailgate for water to pass thru. I've designed the cylinder so that should water get in it isn't trapped and can drain thru the slot which is at the 6:00 position and is also the pocket for the stored J-Hook. Plus the whole thing is held in by the 2 machine screws so it's easy to service. I can readily adapt this to the 47-53 AD's and your input is helping me to decide if I should make a batch for that generation truck. I've made up a mock-up board where I can repeatedly and accurately reproduce the dimensions; and there's only a 1 1/8" difference between the the 54+ tailgates and the 47-53 AD tailgates. That little plastic cap on the S-Link was an after thought and probably over-kill/not necessary as I've found the block magnet keeps the S-Link from dancing around when the gate is closed (no scuffing). The 47-53 AD magnetic arrangement is even less obvious and more stable, considering the 90 degree version of the S-Link.
