I haven't noticed any leaks, but just to be sure, just rubbed silicone seal into the bolt head recesses. See my Tech Terror thread for where I am using the extender. I need every drop of fuel I can get to get through the full AMA competition pattern. I also re-tightened the bolts a couple of days after initial assembly, and did find some new slack to take up! I guess the plastic "settles in" for a while.