P-C FR350 framing nailer problem

[Curt Harms]

I have a Porter Cable FR350 nailer I bought off the bay 3 or 4 years ago, I'm guessing. It was from a shop which is supposed to have done an overhaul on it and the owner never picked it up. That seems plausible. I used it when I first got it and it functioned correctly. I went to use it a few days ago and it would fire but the driver stayed extended with air pressure on it. I figured there was congealed oil or some similar problem. Took the "cap" off, there was oil in there but it didn't seem excessive. I removed the piston/driver and cleaned & re-oiled it. Sprayed some WD-40 on a paper towel and wiped the cylinder down. The cylinder seems in good shape, no residue or scoring. Reassembled, tried it again, same story-fired and piston stayed extended & pressurized.

If I retract the piston with a dowel it still leaks air and will not fire. If I remove the cap without first retracting the piston it will not fire. If I retract the piston with a dowel THEN loosen the cap, wiggle it a little then tighten it, the gun will fire but the piston stays extended & pressurized. I called the Porter-Cable service center. They said the repair could cost anywhere up to $130. I can get a new gun for not much more. To diagnose the problem would be around $21 but they could not reassemble the gun without repairing it due to OSHA regulations. So I could either pay whatever they ask or get a box of parts back.

Something seems to be sticking but I can't figure out what. I don't see any moving parts in the cap, but retracting the piston the loosening the cap fixes it for one shot so something is getting reset. Has anyone run into this? What was the fix? Trigger kit? I did download the manual and parts list. The manual is pretty much useless. Thanks for any insights.

[Andrew Nemeth]

I have a PC framing nailer and I had a similar problem a few years back. The driver was bent and needed replaced. When the service center opened it up to replace the part there was not a lot of oil in the piston chamber. It had been sitting a while before I went to use it and I suspect it dried up. I don't know if the two problems were really related but I can tell you that after replacing the driver and a good lube job, the gun worked just fine. I don't remember it being very expensive. Had I had the time I would have done the repair myself, as I know you can get the part.

As a side note, I'm not sure WD-40 is the best oil to use. It goes on thin but eventually gets gooey. I have found using lubricants designed for air tools seems to keep my guns cleaner (just like my car is faster after I wash it).