SOMETIMES WHEN THE SAFETY IS DEPRESSED AND THE TRIGGER IS PULLED TO CYCLE, THENAILER WILL FIRE RAPIDLY MAYBE 10 OR 12 NAILS WITHOUT STOPPING, I HAVE REPLACED THE TRIGGER O-RINGS AND THE FIRING VALVE O-RINGS. HELP
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Porter Cable Master
Re: PORTER CABLE FR350 FRAMING NAILER RAPID FIRES
I have seen this problem on several brands of nailers. The solution in most cases was to make sure headvalve orings are sealing correctly. Here is a simple test. Remove the head and place on workbench with gasket surface facing up. Push headvalve all the way in with your thumbs then cover the vent hole with finger and release thumb pressure to headvalve. Vacuum should keep headvalve down untill you release finger at vent-hole. If vacuum does not hold, remove headvalve and examine surfaces for fine scratches and/ or make sure of correct size orings (headvalve should be very snug). Remove scratches with extra fine paper (300-400 grit). If headvalve holds, remove headvalve piston and piston stop. With headvalve spring removed, push piston stop into headvalve and make sure that the piston stop fits snuggly into piston. Also make sure piston stop is not damaged or cracked. A loose fitting piston stop will cause multi-fire. Replace as necessary. Upon re-assembly, lube all rubber parts with plenty of silicone lube (not oil, wipe clean all parts before lubing). Silicone paste/grease is sold at Lowes in the plumbing department (Danco Brand). Good luck and email if you have other questions about this gun.
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Could be just a lack of lubrication in the headvalve /orings or the safety foot is not pushing in the trigger pin all the way. Easy to check. Remove the head and pull out the head-valve. Apply plenty of white grease or silicone paste to the orings and the surface where the orings make contact. Install the head and test. If the gun fires then you are done. If the gun does not fire, make sure that the safety foot is depressing the trigger valve all the way in when attempting to nail. Simple test is to remove the trigger exposing the firing pin. With nails removed and air connected, with quick motion depress the firing pin all the way in. If the gun fires make adjustments to safety foot. If the gun still does not fire (with headvalve lubed) replace the firing valve core part # ca0108. Good luck
Nailer not firing is caused by lack of lubrication in the headvalve (lube with white grease) or driver stuck/bent (make sure driver moves freely) or safety foot not depressing the firing pin on the trigger valve all the way in. Easy to check. Remove the trigger to expose the firing pin. With no nails in gun, connect air and depress the firing pin with finger all the way in. If the gun fires, adjust the safety foot. If the gun does not fire, lube headvalve and check driver piston stuck. Good luck
Various nailers will fire on their own when connected to air if the orings have become hard or worn and internal trigger valve parts worn-out (mostly Dewalt and P/C). You could buy an oring kit or purchase trigger valve seperately. Replacing trigger valve and lubing the headvalve with white grease will most likely solve the problem. After repairing the gun, be sure to remove the nails from the mag after each use to prevent possible discharge of nail. Good luck
Normally I would say you aren't using enough air pressure because somewhere around 80psi (every tool is different) will not be enough to fully retract the driver. At 110 you are fine so that is not the case. I doubt it is broken because a broken driver will still retract unless it broke near the piston. My guess is it needs the o-rings replaced but you can pull the top head and pull the driver out first to make sure. Parts and breakdowns can be found here as DeWalt owns Porter Cable.
This is a bottom fire tool. (NV83A2) You need to hold the trigger down and then as you place the nailer to the wood the safety will depress and it will fire once. This is usually done in one, swift action. If you do this in the opposite way by placing the tool to the wood and then pulling the trigger they often will double fire.
The gun will miss fire if the driver does not return to top position allowing nails to move into position. Could be bent driver, faulty trigger, cracked lower bumper or check valve not in place. Easy to check if trigger. Remove air supply, and remove the pin holding the trigger. Fire the nailer by depressing the firing pin with your finger. If the gun works ok, single fire trigger is faulty or safety foot is out of adjustment. If still miss fire, remove head and pull out cylinder and piston. Check for bent driver, cracked lower bumper or black band (check valve) is out of place on outer part of cylinder covering a row of holes.
With most nailers there is a safety device that has to be depressed as you press the gun against the work that is being nailed. This safety device might be damaged or jammed in the firing position allowing the gun to act like an automatic.
The problem that you are describing usually occurs when fine scratches in the head allow air pressure to bypass the orings. Here are a couple of simple tests. Remove the trigger from the gun to give access to the trigger valve plunger. Remove the nails from the gun. While pointing the gun away from you, connect the air supply. There should be no air leaks. Now quickly depress the trigger pin all the way in. This must be done with a very rapidly movement. If the gun fires, then the safety foot is not pushing the trigger pin all the way in. Check for worn trigger or safety mech. When the safety foot is depressed against the work, the trigger pin should be depressed all the way into the trigger valve for the gun to fire. Hold the trigger closed tightly and very firmly depress the gun against the work, the gun should fire. If it does not fire try next test. Remove the head from the gun. Hold it in your hand and depress the headvalve all the way into the head with you thumb. While holding the headvalve in, place a finger over the small venthole on the mating surface of the head and release the headvalve. Vacuum should hold the headvalve in the head for a moment until you release the vent hole. If the headvalve springs back with finger over venthole you must remove the headvalve and inspect the surfaces with maginfing lens for fine scratches. Remove scratches with very fine paper to obtain smooth polished surface. Lube surface with silicone lube (looks like vaseline, sold in small container at Lowes plumbing department used for lubing faucet orings ) re-assemble gun and make sure that you tighten headbolts firmly. You should be ready to work. Good Luck!