Nailer: Leaks Air From Top

If you notice the sound of an air leak coming from the top it could be a leaky seal inside the nail gun. To examine the seal remove the top cap. Remove the seal and inspect it for signs of wear and damage. Replace the seal if need and install a new gasket between the nail gun housing and the top cap. Gaskets should only be used once for a proper seal. Reattach the top cap and tighten the screws a little at a time in an alternating pattern to seat the gasket and prevent it from leaking air.

The piston head valve controls the air flow into the cylinder chamber forcing the piston/driver assembly down on the next nail. If you hear air leaking inside the top portion of your nail gun it could be a defective piston head valve. To inspect the piston head valve remove the top cap from the nail gun. Use a pick to pull out the piston head valve from the cap. Examine the piston head valve for any signs of wear or damage such as worn out O rings, cracks in the piston head valve or anything else out of the ordinary. Install a new piston head valve if it is needed. Clean out the housing. Apply a small amount of Vaseline or lube to the O rings before installing. Reattach the top cap and tighten the screws in an alternating pattern a little at a time to seat the seal.

If you hear air leaking inside the top cap it could be your O rings. O rings inside the top cap around the piston head valve can leak over time with use and will require replacement especially if the nail gun is not getting oiled regularly. To examine the O rings remove the top cap and use a pick to pull out the piston head valve. Examine all the O rings for signs of deterioration and damage. Replace any O rings showing signs of wear and apply a small amount of lube or Vaseline around them and reinstall the piston head valve back into the top cap. (Some valves pull apart and will have an O ring inside. Replace any bad O rings and reassemble the valve). Install a new gasket between the top cap and the housing as gaskets are a one time use. Reassemble the top cap and tighten the screws in an alternating pattern a little at a time to seat the gasket.

Gaskets provide a seal between 2 joining pieces. If air is leaking between the top piece and the housing then the gasket has failed. To replace the gasket, remove the top piece and discard the old gasket. Clean both mating surfaces and install a new gasket. Tighten the screws in an alternating pattern a little at a time to seal the gasket.

If the top cap is leaking it will need to be replaced to keep the air pressure inside the nail gun. Remove the screws and the top cap. Use a pick to remove the piston head valve. (Makes and models all differ. Your nailer may have more parts inside of the top cap, remove everything from the top cap and transfer to new top cap). Install the piston head valve into the new top cap and install onto the nail gun housing. Tighten the screws a little at a time in an alternating pattern to seal the 2 pieces together.

A leaky piston ring will need to be replaced as it will allow air to escape causing a weak drive on the nail. This will result in the nail not sinking down deep enough in the material. To replace the piston ring, remove the top cap from the nail gun. Push up on the driver to remove the piston from the nail gun. The cylinder may come out with it, if it does remove it as well and continue to push up on the driver to separate the piston from the cylinder.

Inspect the piston ring for signs of deterioration, rips or anything else out of the ordinary. Use a small screw driver to remove the piston ring by placing it under and lifting up on the piston ring going around it walking it off. Apply a small amount of lube or Vaseline to the piston ring and the piston then walk the piston ring onto the piston by hand. Reassemble the piston/driver assembly back into the cylinder and reinstall back into the nail gun. Install a new gasket between the top cap and the housing and tighten the screws a little at a time in an alternating pattern to seat the gasket.

A broken collar will allow air to escape. To examine the collar to see if needs to be replace, remove the top cap and pull out the collar. (Note not all models have collars). Pull out the collar. If it is broken install a new collar. If it is not broken examine the O ring around the collar for signs of wear and replace it if it is worn. Install the collar into the nail gun, install a new gasket between the housing and top cap and reattach the top tighten the screws in an alternating pattern a little at a time to seal the gasket.

A repair kit will have everything you need to rebuild the inside of your nail gun and restore it to new condition. Remove the top, the magazine and the bottom nose piece from the nail gun. Pull the cylinder out of the nail gun, (you may have to tap the side with a rubber mallet to loosen it). Remove the piston/driver assembly out of the cylinder. Remove the metal ring that supports the cylinder in the gun. Replace the O rings around the outside of the cylinder, and the metal ring that supports the cylinder. Apply a small amount of grease to every O ring that you replace. (The grease is supplied in the kit). Remove the piston head valve and replace the O rings.

Some models have valves that separate, pull the 2 pieces apart. There are O rings on the outside and one on the inside. Replace these O rings. Reassemble the valve back together and reinstall into the head with the cage. Remove the piston ring by prying under it with a small screwdriver and lifting up and around the ring. Walk it off the piston.

Install a new piston and add a little grease. Install the piston/driver assembly back into the cylinder. Replace the seals inside the nail gun. Install a new gasket between the housing and nose piece and tighten the screws across from each other a little at a time to seat gasket properly. Slide the metal ring over the cylinder assembly. Make sure the piston is all the way down in the cylinder for easier installation into the housing. Install the cylinder assembly back into the housing. Make sure the driver is aligned properly to the opening in the housing and press the assembly into place. Install the top cap with a new gasket and tighten the bolts a little at a time in an alternating pattern to seat the gasket properly. Reattach the magazine.

Next remove the trigger valve by removing the grommet and tapping out the pin. Unscrew the valve or tap out the pins holding the valve in depending on your model. Remove all the O rings and clean the trigger valve and install new O rings. Clean out the housing and insert the valve back into the housing. Reinstall the pin and grommet.