Finish Nailer maintenance advice needed

[Yonak Hawkins]

Recently my Finish Nailer has begun misfiring more and more frequently. That is, when I pull the trigger, it hisses and doesn't fire. I know I had oiled it too much, putting in half a dozen drops of oil every 8 hours or so of work. I have opened it up and wiped oil from the cylinder and piston but the problem persists. I continue to use the same nails and air pressure as I always had. Is replacing the piston ring the answer or is there another culprit ?

[Jim Andrew]

It's a bad o ring somewhere. Could be in the trigger. Just get an o ring set and go through the gun.