I have used Porter Cable finish nailer I bought used.. It is made in Taiwan so a bit older. Plastic cylinder si I do not know if it is oil free or not. The piston failed to retract the last 1/8 of an inch. This means the nail heads can not advance into the line of fire. I took the cylinderhead off and cleaned the cylinder, piston and hammer rod. This helped for 4 shots but now it is not quite retracting all the way again.
Thers is something wrong with the retracting valve action. I pull the trigger and shoot a nail nail. That works fine but then there is a slow hiss for about one second instead of a instant double fire hiss to retract the piston.
Is the valve in the cylinder the retraction valve? Should I take it out and clean it? I do not really understand the valveing for a nail gun.
Bill D