Just make sure what you're smelling is not root beer.
Caustic soda is easy to get rid of. I soak overnight in a mild water/bleach solutiuon. Disassemble and clean all connections and soak O-ring.
If it's a root beer smell, replace the o-ring, or plan on soaking in a strong bleach solution for about three weeks.
Soda bottlers have dediocated root beer lines to avoid cross contaminating other equipment.
I always ask my keg supplier to make sure not to send me any root beer kegs.