Last summer, on a trip down the St-Laurent North Coast all the way to remote Natashquan - beautiful sandy beaches, untamed rivers - in our 2005 Sprinter RV, loaded with bicycles and sea kayaks, at one point, a pot on the gas stove spilled and a few drops went onto the shaft of one of the two burner knobs... Next time I tried to use that burner, the knob was stuck. Finding a replacement part was close to impossible while on the road. The distributor was near Monreal, where we live. After we returned, I checked for replacement parts from the manufacturer... Nope! Might find a leftover in a RV store somewhere, might have to buy a whole new stove...
After disassembly, cleaning and unlocking the conical valve, I realized that the shaft behind the knob had broken its pin which allows to lock to the conical valve. In short, I needed a new shaft - time to get that 3D printer to good use.
Note that you'd better turn the gas off before you play with this.
With the replacement shaft. the knob locks in in the off position, push to unlock and turn to open the gas - just like the original. Sweet!