Dewalt D51844 Framing Nailer - Answered Questions & Fixed issues

This nailers are very inclusive , i have experience issues when i try other nails brands, and when i put DeWalt nails they work just fine. keep in mind that most nailers have a safety that when a couple of nails are in the magazine it wont shoot,

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first of all, you thought it was the orings? why? does it nake any noise( air leaking). make sure, positive, the safety his making contact with the trigger. It goes from the top all the way and makes contact on the bostitch nailers on the back side of the trigger and if its not set allthe way it wont fire. as a repair guy I have found a few to be more odd then others. if you feel comfortable enough to change orings , Ill assume you have had it apart. then take off the magazine an tap out the pin that holds the trigger in, not the valve just the trigger. this way you can bypass the safety and dignose the issue. when you get he trigger out push the button with your finger and air plugged in don't face it toward yourself or have anything over the end. Even with no nails it still hurts a lot when the driver hits you. Trust me on that. If it still doesn't fire do you have at least a 100psi on the compressor?

Most all of my guns are senco and the head has the moving part for fire and reload,, controlling the driver piston. Multiple shots suggests a trigger problem. No water in system right.. Well Its all O rings little ones,, skinny ones,, fat ones etc. You can open it up and check, do the head first, I think.. Its fast a off and on

If it has a depress style safety it might not be traveling quite far enough to fire.

NO. Machine oil or 3in1

Bad O ring in gun most likely. Usually happens on mine in the fire/reload phase. If its an oil lubricated gun give it a squirt of 3in1 if that doesn't help it will have to go to the repair place..

disconnect air and pound up the driver blade with a punch and nail should fall out.

I always lube the O-rings, seals, and the inside of cylinder with o ring silicone grease,,,I get mine from the Oringstore online

Just pull the pusher back along the magazine all the way until it latches. It should be located on the side of the magazine and looks like something you can grab with your fingers. Then load the nails in through the slot. Pull back on the same pusher until it unlatches and it should slide forward to push the nails toward the head.

Remove the nails and remove the trigger to expose the firing pin on the trigger valve. Connect air and very quickly depress the firing pin all the way in with finger. If the gun fires, adjust the safety foot to depress the firing pin all the way in. If the gun does not fire, most likely the problem is that two orings that make contact with the cylinder spacer (white plastic piece around the cyl.) and the cylinder are leaking between the chambers. Check for snug fit as spacer could be worn. Pull out the cylinger and remove all the lower parts so that you can slide the cylinder in and out of the spacer. The cylinder should fit snuggly into spacer and have some resistance. Try with one oring installed on cylinder , then both as one or both may not be snug enough. If it fits loose, install a couple of winds of Teflon tape into oring groove then reinstall the oring. Again check for snug fit (or replace the spacer if surface is scratched). Reinstall using white grease and retest. Good luck.

If the nails are stuck in the rails, remove the rails and fish them out. If a nail is stuck between the driver and nose of the gun, you will need to forcefully push the driver back into the gun. Remove the head and cylinder and place the body of the gun on piece of plywood with nose pointing up. Using very sturdy steel rod, hammer the driver down. The steel rod needs to be slightly thinner than the driver to allow for the stuck nail. I use a broken driver ground thinner on the side that will need to bypass the stuck nail. Careful when striking hard steel with hammer, could spinter (I use a heavy brass hammer). Good luck

Air leaking out the nose indicates that the orings that seal the bulkhead /cylinder spacer (white plastic ring around the cylinder) are leaking. Order oring kit from dewalt and replace all the orings. I dont remember if the kit containes a trigger valve but it needs to be replaced also or at least have a spare ready when the orings in it fail. Dewalt used some vinyl-like orings that failed (vinyl orings were also used in the trigger valve ). Good luck.

Dewalt uses about 4 or 5 orings within the gun made of semi clear urethane that fail (turn gummy and breake apart). Two are under the bulkhead and at least two in the trigger valve. To remove the bulkhead pull up on the white housing. With housing and cylinder assembly out, push down on the black retainer at the very bottom and remove the oring(take a picture of the assembly after each stage so that you can re-assemble the spring and checkvalve correctly). You will find two large orings under the bulkhead against the cylinder that need to be replaced (also the orings in the trigger, or replace the trigger valve ).

Air leaking from middle section of the gun.Most likely the orings between the cylinder and cylinder spacer and orings sealing the cylinder spacer to the body. The cylinder spacer is the white plastic piece visable when you pull off the head. Order the oring kit and replace all the orings in the lower part of the gun. Dewalt used some vinyl orings on the cylinder that failed. The trigger also has orings that will fail. Good idea to order a trigger valve and have it ready( or replace now if the gun is several years old). Good luck and post again if you have question about this gun.

Yes it is most likely the o-ring has gone bad. I would suggest that instead of just buying one O-Ring you purchase the o-ring Kit You can order them Here

You need to look at the model plate and see if you have a Type 1, 2, 3, Or 4

The problem that you are experiencing could be caused by several conditions within the gun. Lets work thru the possibilities. First make sure that the nails are correct for the gun. Place a stick of nails on the outside of the magazine with the first nail aligned with the path of the driver. The stick of nails should align perfectly with the path of the driver and also with the magazine. If they do not, don't use the nails. Check with dealer for correct nail. I find that short nails (around 2") will have a tendancy to jamb.
The driver will not travel to top of cylinder if the driver oring/ring is too worn or the driver is bent. The driver should fit snug into the cylinder but be able to travel rather freely . At the bottom of the cylinder check that the bumper is not missing pieces or is cracked. Some nailers have a washer below the bumper that fits snugly around the driver shaft. The bumper and washer prevent too much air from leaking down thru the nose and helps to push the driver back up to top. There is a check valve around the med section of the cylinder that is what actually caused the piston to return to the top with force. You must remove the cylinder to check. Parts are available at www.toolpartsdirect.com. There is also a rebuild kit for this gun. Enjoy

Dewalt uses two vinyl orings against the cylinder spacer seal. Most likely one or both have have failed. These orings are included in the repair kit available thru dewalt service center near you or on the web. If you have a source for orings, like a bearing retailer, you could replace with generic viton orings. Take cylinder and cylinder spacer with you so that you can fit them in. The orings should allow cylinder spacer to fit snuggly and allow the spacer to have about a 1/4 in travel without jamming. If a kit is not available, then only option is to convert to generic orings. Good holidays

Dewalt uses two vinyl orings against the cylinder spacer seal. Most likely one or both have have failed. These orings are included in the repair kit available thru dewalt service center near you or on the web. If you have a source for orings, like a bearing retailer, you could replace with generic viton orings. Take cylinder and cylinder spacer with you so that you can fit them in. The orings should allow cylinder spacer to fit snuggly and allow the spacer to have about a 1/4 in travel without jamming. If a kit is not available, then only option is to convert to generic orings. Good holidays
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Dewalt nailers have some orings made of vinyl in critical sealing areas that failed due to oil/water in the supply air. One indication of failed cylinder seal orings is leak out of nose. You could replace the individual orings or order oring kit #610773.01 from dewalt service center or on line at www.toolpartsdirect.com. Second option is to take gun to a fastener outlet that also repairs the popular brands of nailers and ask them to match orings with better viton type seals instead of vinyl. If you are handyman type, pull parts out of gun and take worn orings (and parts) to bearing dealer and they will measure your seals and sell you some oring lube. Good holiday