This is the Service bulletin that Van's sent out for the Fuel pick-up tube. Apparently there where some that had backed off. This is the way I did it. Vans SB had the safety wire wrapped around the 90deg fitting before it exits the cover plate. I drilled a .040 hole in the Anti-rotation bracket and safetied to that. Much cleaner and has no way of rotating. The first shot at drilling the hole in the Nut went through to the threads so....I didn't like the hole through the threads so I replaced the entire tube. I did a better job than Vans did on the QB tube.