Well, after about 100 refills, I was starting to see some leakage while filling my Flame King propane tanks. Nothing terrible, and only happened while refilling, but not ideal and I wanted to either replace them or fix them. I contacted Flame King and they sent me some O-Ring repair kits. I spend a while looking at the kit and wondering how the heck I'm supposed to fix my tanks with the supplied parts since there were no instructions. I decided to just dig in and figure it out as I went.
Turns out it was was pretty darn easy.