Hi all, My Primus 2396 Vintage Stove is sometimes leaking gas around the green knobs. The stove works great most of the time, but other times there are some issues and everything goes in fire which makes the stove unusable and dangerous. I suspect the little black seals to be worn out. I would like also to buy a replacement green knob because one is missing on my stove. Please find the attached picture to see what I mean. Thank you !