My hitachi nail gun won't fire,I opened back up and fan is lying loose inside.Can I fix this

Have you disconnected it from the air source and deep cleaned the nail gun? Sometimes even a tiny bit of dirt can block the rails the rod runs in. Once cleaned add a small amount of oil to the rod runners.

gas pattern valve ?

First thing is , when did You clean it last?

If gun firing but nails not being driven could be one of two basic problems:
1. Nail jammed in magazine not allowing nails to move up.
Empty magazine, does follower move to top of magazine. Push gun against work piece, does fan motor start? Yes - jam in magazine or lock out bar not operating. (this would allow nail un to fire when out of nails)
2. Piston/driver not returning fully after firing, hence driver blade on top of next nail instead of behind it. This could again be caused by a jammed nail or just a nail head. Another case of not returning is the combustion chamber not making a good seal, check O rings on framer (they are steel rings on bradders) it may just need a good clean it is surprising how dirty they can get and if not cleaned a build up of dirt could break a seal. If not been cleaned for a long time worth checking piston rings, worst case scenario dirt builds up around the rings and stick fully in requiring new piston if the rings will not come out.
Nail guns work on the principle that an explosion pushes the piston driver forcing a nail into the work piece, after the explosion a vacuum is created and it is this that 'sucks' the piston/driver back up the cylinder.

NV50 nailer is very difficult to repair due to complicated feeder /feeder spring / feeder retainer pin design. You most likely need to replace the orings on the feeder piston. Problem is that you must remove the feed pin/ spring to get the piston out. If you are going to attempt to replace the orings, study how the pin is installed otherwise you will make it worse. Order new springs (2 different springs ) and install them when you are going back together. Good luck

This gun should be bump-fired only. Do not place the gun on the work and press trigger. Make sure that the safety spring is in place and has good tension. The spring helps to push the foot off the trigger so that it fires once. You could also adjust the screw that pushes on the firing valve. Turn in or out several turns till head of nail is correct when bump firing then lock the nut. The safety foot fits rather loose on the gun and should still work ok but can get so loose that it falls off the nose. Good luck

Best practice is to bump fire the gun to prevent double fire. Do not place the gun on the work and pull the trigger. This takes practice while using at an angle. Works better if the nose piece has rather sharp points to help nose to stay in postion while you bump. With trigger depressed, practice without nails bumping/hitting wood at different angles untill you can bump hit at the spot that you need the fastener. If the gun double fires while bump-firing, most likely all the safety/trip parts are worn/loose. Not expensive to replace. Good luck.

Your nailer is a very heavy duty nailer with very powerful blow. Works best with full size nails, not 2 inch range that are used in fencing, they are not spaced correctly for your gun (like hitting number 6 nail with sledge hammer). Open side door and remove the nails, leave the door open and dry fire gun against piece of rubber or old coiled air hose. The driver should return all the way up between shots and the feeder should move back then forward just as fast as the driver moves. If the feeder seems to move in slower motion then pull feed piston and replace orings and remove debris from feed cylinder. If the driver seems to stick out further than normal then lower bumper could be breaking up causing debris to enter feeder. Make sure that the driver is not bent and has a squared bottom, if rounded, remove and grind square. Finally adjust the depth control up or down slightly and bump fire for test, do not place gun on the work then fire. good luck

Hi,
It is common to see sparks. It is metal striking metal. Although, if it sparks alot. It could be a chipped driver blade and the nail would not drive all the way. Does your sink `em?

Does the fan run and the light blink ont he nailer? I have one that I just bought. I put in the wrong type of nails and got one stuck. I had to take the front apart to clear it and now the damm thing wont fire. The green light blinks and the gas cartridge is basically full, even the fan does run after I release the push lever, but no fire???

I wonder if yours is the same as mine did fire for a couple nails first just fine then got jammed...

I will try to charge the battery more.... MAybe like yours it needs a strong charge for the spark...
Russ