How do I Repair a Bostitch Coil Nailer N12?

The Bostitch N12 was the first of Bostitches coil nailers.

An allen key, hammer and metal punch are the tools required to rebuild your nailer.
It is no longer in production. The only parts widely available are pieces compatible with other models, such as the trigger valve and driver cylinder seals. Fortunately, these are the major repairs required by most air nailers. For other repairs, you will probably need to find a tool repair tech who has a stock of parts still on the shelf. A replacement tool may be less hassle and expense if repairs needed are in the fastener clip. .

Remove the trigger by pressing the roll pin out at the top of the trigger. Lay the gun on its right side and use a small metal punch and ball peen hammer to tap the pin out and remove the trigger. Remove the roll pin in the handle, directly behind the trigger, in the same way.

Withdraw the trigger valve from the handle and remove the black rubber band seals around the valve. There are two. Replace them with new seals of the same size, fitting them into the grooves on the valve body. Fit the valve back into the handle and press it into the handle.

Turn the gun over to its left side. Align the trigger with the hole vacated by the roll pin. Press the two roll pins back into place, tapping them lightly with the metal punch and hammer.

Remove the four screws from the square black cover on the back of the gun, above the handle. Use an allen key to turn the screws counterclockwise to loosen and remove them. Lift the cover from the tool. Push a small metal rod through the barrel of the tool and press the driver cylinder out the back of the tool. Remove the black rubber O ring seals and replace them as you did with the trigger valve.

Press the driver cylinder back into the tool and push it all the way forward to seat the O rings. Replace the cover. Install the four screws and tighten them with the allen key.

Things You Will Need

  • Allen key
  • Hammer
  • Metal punch
  • O rings

About the Author

Mark Morris started writing professionally in 1995. He has published a novel and stage plays with SEEDS studio. Morris specializes in many topics and has 15 years of professional carpentry experience. He is a voice, acting and film teacher. He also teaches stage craft and lectures on playwriting for Oklahoma Christian University.