I had a similar issue with mine when I originally purchased it. A little tinkering with the air tube fixed it. Upon taking the grips off I noticed it just needed a half turn in on the tube to fit correctly.
Try taking your grips off with the tank screwed in and flip the level. If it leaks flip it back off and adjust the air tube a 1/8 to 1/4 turn. Flip the lever again and see if it still leaks. Both ends thread so be sure to try adjusting both. This fixed mine, hopefully it fixes yours.
Edit: when you have the grips off and air up the gun you should be able to tell if it's leaking from the top or bottom of the tube. Start off adjusting the tube from the end it is leaking.
Last edited by surflamj : 07-29-2014 at 10:59 AM.