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I have a Hitachi NV 45AB roofing nailer that is leaking a lot of air from the exhaust hole. I just replaced all of the o rings in the nailer and it did not help anything. Could this be a bad exhaust valve?

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You replaced all the orings and I take it that you lubed them a little with a light grease. By exhaust valve I assume you mean the plate on top and if so it could be a couple things does the air leak out when you connect the hose and don't do anything if so if you have a dead blow hammer try "tapping" on the top cover with the air connected, some times when replacing the rings the cylinder doesn't seat right away. If it leaks when you depress trigger then I would look for a cut o ring. Let me know and we can fo further

Posted on Mar 11, 2009

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