mine was actually breaking at the cap. just above the threads on the cap it would crack. it's done this twice now... so time for something different.
last night i mounted my manual fuel pump to my flight box and then drilled a hole in the top cap for the fuel jug and mounted the filler there. it seems to be a pretty good seal so far. i may look for another type of cap as this one is double layered and may not seal quite as well.
ORIGINAL: pkevinb
I have the same thing and have the same problem. The red nut on the underside of the cap is constantly coming loose. I need to get a lockwasher for it someday because I am constantly having to re-tighten it. I haven't got frustrated enough by it yet to actually do something though.