Assuming you are using one of the Ronson style filling valves, check to see if the leak is coming from the outside threads. If that is the case, put Teflon tape on them and see if it seals. If it's the filler valve, you must replace it. These fillers are a pain in the butt and are totally un-reliable pieces of junk. I always keep at least 2 spares in my tool-box. Dab a little soapy water around the valve to check it.
Phil > The Steamlines Shay butane tank valve has developed a leak. > When I fill it the valve allows lots of butane to escape before it seals. > What are the repair steps? > BTW ~ The fuel economy saved by installing the radiant burner is completely > counteracted. Run times are about ten minutes from first firing to running > about four minutes. > Gary - Eugene, OR >