Ive had this gun for a while but recently i tried to use it and it wasnt nailing right. just a little bit of air comes out when i press the trigger and im not sure what it could be.

The trigger valve should release air when depressed. This release of air comes from behind the head valve. If the head valve does not pup-up when the trigger is depressed then air is leaking past the head valve orings. Try coating the head valve orings with plenty of white grease and retest. If the gun fires you know that orings are leaking. Test with no more than 100 psi. Good luck with your repair.

I presume the gun fires but no nail is ejected. A possibility is jammed nails in the magazine. Do you see a mark in your work piece of the driver blade? If yes then it is most likely jammed nails. If not could be a broken driver blade. If gun does not fire could be gas problem. (check in date, yes it does have a use by date), another cause of not firing is a broken wire particularly around trigger switch (switch is on trigger and hence the wires are flexing every time trigger is pressed). Another cause of not firing is a brass spring clip in handle assy if this breaks it stops the gun firing. Recently I have had more broken wires than anything else on these guns. Worth noting is that the Stanley Bostitch nail guns suffer the very same faults. Also note they are the same gun just different colours so you can fit Hitachi parts to the Bostitch and they are cheaper.

If the trigger is set to single fire, you will need to place the gun against the work then pull trigger as you have done. Try setting the trigger to bump fire and try again. If hear a thump inside the gun, remove the head and check that the head valve in not stuck from lack of lubrication. Easy test, remove the nails, remove trigger pin, remove trigger and manually push trigger firing valve. If the gun fires then suspect faulty trigger or safety arm not lifting enought to activate the trigger valve. Good luck

May need a new firing valve or safety foot is sticking. Easy to check, Remove air supply, nails and remove the trigger to expose the firing pin. Connect air and place the nose of the gun against thick rubber or coiled air hose. Depress trigger and let go. Gun should fire and trigger pin will return to original position. If piston still does not retract then problem is with trigger valve and most likely the rest of the orings within the gun will need replacing. Not expensive. Remove the air supply and look closely at the firing pin, if it moves quite a bit from side to side and looks worn time to replace. If it look to be in good condition, then orings within trigger valve may be swollen and will not allow the trigger to function. You can remove the valve by removing the 3mm roll pins above the valve and applying air pressure to pop out the valve. Use heavy glove to catch the valve because it could come out with force (reduce air pressure to gun if possible). If gun works ok examine safety foot mech for problem. Use silicone paste lube on orings. good luck

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.

It sounds like the air pressure on your compressor is too high..lower it and see if your gun shoots better.

On some models the contact fire is not available. There is a flap that is under the actual trigger. When you press the safety in, it engages this little flap which allows the trigger to be engaged. As soon as the safety comes up this little flap falls back down disengaging the trigger.

There is an optional trigger assembly that you can put on this nailer. You need parts 174299 and 174300 to make this gun a contact nailer.

Hi there .
First check if the nail gun have a adjustment screw . Depending on the brand could be in the front where the nails comes out or by the trigger. Second check the compressor by the air hose connection you should have a regulator valve with a gauge and see if you getting the right air pressure .
Hope this help

Take head off of tool. Clean and lube orings on the head valve . Do not use wd40 use air nailer oil.

get a senco