My Nailer is Leaking Air

FramePro325XP product photo

Down on power? Hissing sound? Here’s what to do if your nailer won’t hold air.

While durable and reliable, pneumatic nailers need occasional maintenance. If you notice your nailer is down on power, or if you pull the trigger and nothing happens, it may have an air leak. If you hear the hissing of air from somewhere on the nailer, that’s a dead giveaway that your nailer isn’t holding pressure.

However, an air leak doesn’t necessarily mean you need a new nailer. Usually, problems are easy to diagnose and fixable with a little bit of work. Here’s what to do if your nail gun won’t hold air.

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Troubleshooting Air Leaks in Your Nailer

If you can hear or feel air escaping from your nailer, you can often determine the cause by where the leak is coming from. There are several common failure points, such as:

Hose Fittings: If air is leaking from your compressor hose fitting, check to make sure thread sealant tape has been applied to the threads and that it doesn’t need to be replaced. Wrapping your threads creates an airtight connection between the hose and the couplers that connect to your nailer and compressor.

Air Fittings

Compressor Hose: If air is coming from elsewhere on your hose, check for cracks and holes. Hoses often break close to the fittings – use a swivel coupler to prevent wear and tear at the connection point. Hoses can dry out and crack over time, or they may be damaged on the job site by a piece of equipment or a stray nail. It is best to replace the hose with a high-quality PVC hose. (Duct tape may buy some time, but it is not a long-term solution for a broken hose.)

Compressor Hose

Exhaust:  If air is continuously leaking from your tool’s exhaust port, you likely have a faulty O-ring or a damaged seal near the head gasket. Typically, this is the result of a faulty piston-head ring. O-rings and seals are responsible for preventing air leaks from your nailer’s cylinder, and they are generally easy and affordable to replace. Learn more about replacing O-rings.

Tool Exhaust

Top of the Nailer: If air is leaking from around the cap near the top of the tool, it is mostly likely the result of a specific seal drying out and cracking, or becoming damaged. This seal is called a collar. Replacing a broken collar is straightforward, requiring you to simply remove the cap, remove the old collar, and slide a new collar into place.

Trigger: The trigger valve regulates the flow of compressed air into the nail gun. A faulty trigger valve or worn-out valve seals can cause air to leak, reducing the tool’s efficiency. Air leaking from the trigger could be caused by a faulty piston head ring or by a seal inside the trigger assembly itself. You can try replacing the O-rings first. If that doesn’t work, you can replace the trigger assembly for a fraction of the cost of a new nailer.

Damaged Tool: High-quality nailers are built to take abuse on the job site, but you’ll want to check for damage if you can’t find the source of the air leak and if replacing seals doesn’t do the trick. If there are dents or cracks in the nail gun body, you should purchase a new nailer rather than trying to repair it.

Learn More About Troubleshooting Your Nailer

Addressing the issue of air escaping from a nail gun requires a systematic approach. Regular maintenance, inspection, and timely replacement of worn parts will help extend the lifespan of your nail gun. Remember to consult the manufacturer’s instructions and, when in doubt, seek professional assistance to ensure safety and accuracy while working with pneumatic tools.

For SENCO tools, you can easily find your nearest service center through our dealer locator. Click the locator, share your location, and click “Service & Repair” near the top of the map.

If you are attempting to repair a SENCO tool yourself, our technical support assistance is available Monday through Friday from 8:00 A.M. to 5:00 P.M. EST. They can be reached by visiting the contact us page on our website or directly by email at