If I recall correctly, I had similar leak very close to the tank on my M6040 and could not locate it untill I drained the tank and dropped it. At which point I could see it was just upstream [downstream] of where it connected to the nipple on the tank and was actually accessible without pulling the tank. I Think I just cut the hose beyond the leak and spliced in a short repair piece. It has been working fine for a few years now.