Troubleshooting Air Leaks On A Pneumatic Tool

Have you ever tried firing a pneumatic nailer, only to hear air leak when pulling the trigger? If so, you're not alone. Over time, wear and tear will take its toll on any air tool, regardless of the brand. The best way to prevent an issue on the job, practice preventative maintenance. Keeping pneumatic tools properly lubricated with air tool oil, as well as cleaning them regularly will help prevent wear. Storing tools in plastic helps to keep dust and other elements out - especially when sitting for extended periods of time.
But what about the unavoidable issues, like an occasional air leak?
If you try to fire a pneumatic nail gun or stapler, but only hear air leaking when engaging the trigger, it's likely that your tool's "O-Ring" is not sealing properly. When the trigger is not depressed, you may not hear air leaking, as the valve is probably sealed. However, once you engage the trigger, the valve looses its seal, therefore creating a gap for the escaping air you hear coming from your air compressor, as it flows into the tool.
On a properly working pneumatic tool, when air is forced into the firing valve, this pushes the valve upward, which opens the main cylinder sleeve and allows the air to drive a fastener. If the "O-Ring" fails to seal, the air will escape, creating your leak.
While this may seem to be a complex repair, don't get rid of your tool just yet - fixing the issue may be easier than you think. Simply stretch the "O-Ring" on the firing valve and apply grease. This should take care of the issue - helping your air tool run properly. Keeping a tool's "O-Ring" lubricated will increase the ring's lifespan, and prevent drying out.
We must note, this is not the only cause for a pneumatic nailer or stapler to leak air, just a common source when troubleshooting a leak.
Always remember to stop using your air-powered tool - or any tool - when it is not functioning properly. Take your tool to a certified repair technician or complete any necessary adjustments yourself, before using the tool again. Failure to take the necessary preventative measures can result in injury, or can lead to further damaging of your tool.
Like this article? You may want to learn more about choosing the right air compressor for your application. An under-powered compressor can also lead to misfire or weak firing of your pneumatic nailer.
Here's To Many Years Of Service From Your Pneumatic,
The Team At Nail Gun Depot
Leave a Reply


  • Sue Jackson November 21, 2016 at 12:09 PM

    Do you sell replacement O rings for the ISM AB100T pneumatic staplers? What kind of "grease" do you recommend?
    We purchased a stapler from you in 2011, so I need to repair or replace now.

    • Nail Gun Depot November 22, 2016 at 7:22 AM

      Sue, I've forwarded your request to our customer service team, who will contact you shortly in regard to options for repair versus replacement. Thanks for contacting Nail Gun Depot!

  • Randy L December 20, 2017 at 5:19 PM

    Hitachi NT65MA2 15-Gauge Angled Finish Nailer
    My gun started hissing air from the head and it had air coming out the exhaust port. It started very light and it got worse and I was working till I had to get another gun hooked up and going.

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