After sitting untouched for too many years, the fuel tank caps didn't want to come off immediately, but I got them loose eventually:
I disassembled the caps so I could clean out the old grease and replace the ancient o-rings:
Since I started this project, Vans has switched to a different style of fuel cap, so information about this type is getting harder to find. Click here for an exploded view.
I decided I wanted to improve the cosmetic appearance before engraving, so I got out my granite surface plate and wet-sanded the caps and levers using a series of progressively-finer grits. The hardest part was flattening the rough castings using 220 grit; each successive grit after that went pretty quickly.
I progressed to 600 grit, not quite a mirror polish, then applied a vertical brushed finish using a grey scotchbrite pad. I didn't worry about making this look perfect, since these will inevitably get scratched up, but I'm happy with the results:
After researching the fuel tank labeling requirements and the fuel type specifications for my engine, I sent the caps off to Aircraft Engravers. A few weeks later, they came back looking like this:
New o-rings installed and lubed, latches adjusted, and caps reinstalled on the (very dusty) tanks:
