Air leaks when triggered and no nail

It sounds like the nail gun might need a lower end seal/repair kit.

You will have to take the gun apart and change the rubber o-ring gasket for the trigger mechanism..Go to a Home Depot or other contractor outlet to get parts or info...The gasket actually keeps the air from leaking so it will nail.

Air leaking from the bottom of the gun (path of driver) indicates that cylinder seal orings are leaking (if without nails in gun the driver is slowly pushed down the cylinder when air is connected then cylinder seal is leaking ). Cylinder seal snaps on the top of the cylinder and should fit snug and have no cracks. Easy fix for cylinder ring. Remove head and pull out cylinder. Then remove the cylinder ring (part #n50015). Examine ring for cracks and replace as needed. Examine body of gun where spacer oring makes contact and sand fine scratches. Replace orings as needed. If air is leaking between body of the gun and nose casting, replace gaskets. Good luck.

depends on where the air is leaking from, if the top of cap you have a pinched o ring, from the bottom of tool you have a problem with the cylinder or seal, the trigger assembly has a broken o ring. Let me know where the air if coming from and I will try and help.

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.

I had a similar problem with one of my nail guns. What I found was a small rubber o-ring in the trigger mechanism had split. Once I replaced this the problem was corrected and the unit functioned fine.

You could replace the whole trigger assembly for about $35. But if you remove the assemble and replace the split-ring this would only cost a couple of bucks at most.

Trigger assembly shown below. ereplacementparts.com is one possible source for the trigger assembly others can be found on the Internet.

the trigger assembly would need replaced. I have detailed instructions in the tip section on the removal and installation of the trigger valve. Let me know if you still need more assistance.

Remove the nails and air supply. With side door open notice position of driver. Driver should be at top position with tip not visible. If driver is down and it moves within cylinder when you tilt nose up then down again, time to replace orings. If driver is down, it should extend past the nose about 1/4 inch (if driver is broken at the tip the end will look rough and nail will not drive in all the way). If driver extends past the nose more than 1/4 inch then lower bumper may be breaking up /cracked. Easy test for proper function. With nails removed and side door open, connect air to gun and dry fire gun against hard rubber or old coiled air-hose (with air connected and trigger depressed, no air should leak from trigger area, if air leaks when trigger is depressed, look for fault at trigger pin). Feeder should move back then forward in quick motion almost matching speed of driver and driver should not creep down between shots. No air should leak from nose of the gun (push nose against hard rubber and depress trigger and hold in this position, driver should stay down with very little or no air leaking out of nose, when you release trigger, driver will return). If air leaks out of nose while holding in this position, replace lower bumper. If a quantity of air leaks from valve in front of trigger, cylinder orings may need replacing or outer part of cylinder has fine scratches (remove scratches with 400 grit paper). Parts are available at www.toolpartsdirect.com. Good lucki

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 you took the trigger apart the part that you unscrew has a nylon ball and a black rubber ring you should check them and make sure that you didn't loose them when you took it apart,if they are there, then you need to service the gun, and after you clean all the moving part and you put it back together, it may still leak from the top,Take a rubber hammer and give it a good hit,now not to hard, and it should seal