The gun had a slight air leak at the trigger. The repair shop put in an o-ring kit. Works great on their shop compressor. Plugged it into 2 different portable compressors and air leaks continuously fr

you may have to rebuild it again. inspect nail gun piston cylinder to ensure that it is not worn or scratched. Is the gun lubed before each use and periodically under heavy use?. Water from compressed air will damage gun.Use quality parts use buna n o rings not buna o rings
good luck

https://www.ereplacementparts.com/repair-center/article/7451/How_to_Install_an_Overhaul_Kit_in_a_Porter_Cable_Nail_Gun.html

Roger, what PSI are you running on your portable compressors? Sometimes these guns will not operate properly if there is not enough air pressure. I have seen some guns that if the air pressure is too low that they will not seal up properly and act as if there is a leak. If you can adjust your portables make sure that your setting is at least what the minimum setting for your gun calls for and then adjust upwards if you need it to drive deeper. Hope this helps.

Shooting continusously caused by worn orings in the trigger valve and in the gun.Dewalt framing nailers use some vinyl orings (gold or clear in color) that fail too soon in both the trigger and the cylinder spacer (white plastic). Air out the nose of gun indicates air is leaking past the cylinder spacer seals (If piston is pushed down with air leak then headvalve seal is leaking (remove nails for this test)). If piston is not pushed down with leak, remove head and pull out the cylinder with cylinder spacer (white plastic). Place the cylinder on workbench with bottom up. Push down on locking ring and remove retainer to release all the other parts. Take picture or take note of parts together and as you pull them off to aid in re-assembly. You will need to replace the two orings between the white cylinder spacer and the cylinder. Order oring kit from dewalt or just purchase one ( # 141 universal oring ) and one metric oring 74.4mm x 3.1mm from hydraulic parts store. If the piston was pushed down with air leak, replace headvalve orings in the head. The trigger valve also has vinyl orings on the trigger pin. You could try replacing the orings but hard to find . Pin uses 2mm x 1.5mm. The orings on the inner valve should fit snuggly on the outer contact surface. If the valve just falls out the the body, the orings are too loose or the body is worn. I would just replace the trigger valve to be safe, however repaired works ok if you can find the orings. Trigger orings do not come in the kit. I would also remove the nails after each use and only reinstall them after air is connected and gun seems to work as it should. The Good luck with your repair.

A new trigger valve and o-ring kit will give you a like new gun. Just remember to replace all available o-rings in the kit, lightly grease all of them as you reassemble the gun and use pneumatic oil at the beginning of the day so you won't be doing it again in a couple months.

Easy fix if air is leaking out the top of gun. Remove the head and lube with white grease or silicone paste. If orings seem to be loose, order repair kit from dewalt (you can tighten orings by removing the oring and wind a bit of teflon tape in the oring groove). If air is leaking from the trigger, replace the valve. If air is leaking out the bottom where the nail ejects, pull out the cylinger and lube the orings that seal the cylinder to the body of the gun.

I replace the trigger valve in my dewalt air gun It is still leaking air I use the right kind of grease on it

A nail gun works on compressed air.
When you hook the air hose to the gun it fills a cylinder with air pressure.
When you pull the trigger. the cylinder pressure is released onto a firing pin that shoots the nail.
The air pressure line is also connected to the trigger and therefore the trigger has to be sealed.

When ever using a nail gun, you add a bit of gun oil in the back of the gun (not 3-in-1motor oil, it has to be non-detergent gun oil)

If you haven't used the gun in a while, it is best to oil up the gun and let the oil run down into the gun.
If you use anything but gun oil, the seals will give out.

Your trigger seal has given out. It is probably an 'O' ring. You can access it by taking it apart. Look for the O ring.
Bostich makes re-build kits for the different guns that you can buy on-line.
Back when I was in construction, there were several nail gun shops that sold and serviced nail guns, and sold nails to the contractors. I don't know if that business model is still active or if you have to send the guns to Bostich service center.

If the trigger still works to fire the single shot, then the o-ring kit should be sufficient. If the trigger area continues to leak air, then the trigger should be replaced as well. Keep the gun well lubricated as well.

Dan

prolly clogged, buy a rebuild kit and use it making sure all parts are totally clean before reassembly. in the future be sure to drain your compressor at least daily after use (more on wet or humid days) to avoid this

You can repair this gun. Parts and breakdown are at www.bostitch.com look for service /parts and enter your model number. There you will the parts available for purchase. You will need the tva11 trigger valve. Easy to install. Remove roll pins that hold trigger and trigger valve. Remove the trigger to expose the tva11 valve. With the roll pin/s removed that hold the trigger valve you will be connecting air supply. Use heavy glove to catch valve as you apply air pressure. You may reduce pressure to airline to reduce pop-out force. Before you install the new valve check port for sharp edges and debris. Good luck with your repair.