DeWalt D51257 has been lightly used for home projects but it stopped working. When trigger is pulled, only air is coming out (through the trigger area) but no nail is fired. Should I replace the trigger valve? Cylinder and o-rings looks ok. Thanks for any advice.

  • Check to see if a fragment of a nail is blocking or interfering with the operation of the hammer. – Jim Stewart Aug 12 '17 at 15:06
  • Checked, found nothing blocking... one thing I noticed was when I engage the safety lock, I can hear small amount of air leaking there. – user74219 Aug 12 '17 at 15:25
  • Did you open the front to expose the drive pin to see if it is retracted entirely? If it does not retract entirely it will leak air when the trigger is pulled. I have had nails jam behind it and keep it from retracting and had to pull it up by hand exposing the nail behind it. Disconnect the air before doing so. – Jack Aug 12 '17 at 21:26
  • Thank you very much for your thought. I opened the top and took out the cylinder and the piston. I don't think there was a nail stuck inside. I suspect the O-rings are bad? – user74219 Aug 14 '17 at 16:47

I had this issue on a Makita siding nailer. 1 week old, was working perfectly the day before. Checked that the piston wasn’t stuck, opened it to see if residue was affecting the o-ring; everything was fine. In frustration, I held the trigger down while pressing the nozzle against the material. After about 5 seconds the gun finally engaged. Working perfectly again.

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