Hitachi NV45AB2S Coil Roofing Nailer Logo
Posted on Apr 23, 2009

Rebuilt nail gun and now it just blows air out the exhaust port

I have a hitachi nv45ab that was in desperate need of new o rings. I bought the kit and a service manual and followed step by step replacing every o ring in the gun. Now when I plug in the air line the gun just blows air out of the exhaust port. Its not a small leak it just blows all the air right through the exhaust. I have taken the gun back apart 3 times now and still come up with the same result. I do have one o ring left over from the kit its numbered 9 in the service manual valve o ring. It is supposed t sit on the head cap but there was no o ring there when I took it apart. I have tried to put the o ring in but do not see where it would go. And every place I have tried does not make a difference. I have another working gun but I am affraid to take it apart to look if it has the o ring in it. I dont want to have two guns that dont work. Please help.
-Alan

  • firemane82 Apr 23, 2009

    Thank you so much for the quick response. The gun works like its brand new again. I cant believe it was that simple.
    -Alan


  • Anonymous May 02, 2018

    This was my problem as well. Runs like a champ now!! Thanks so much!!

×

1 Answer

Anonymous

Level 1:

An expert who has achieved level 1.

MVP:

An expert that got 5 achievements.

Governor:

An expert whose answer got voted for 20 times.

Hot-Shot:

An expert who has answered 20 questions.

  • Contributor 25 Answers
  • Posted on Apr 23, 2009
Anonymous
Contributor
Level 1:

An expert who has achieved level 1.

MVP:

An expert that got 5 achievements.

Governor:

An expert whose answer got voted for 20 times.

Hot-Shot:

An expert who has answered 20 questions.

Joined: Apr 18, 2009
Answers
25
Questions
0
Helped
39496
Points
60

This probably is the problem,

The cylinder that the piston moves up and down inside is probably to low, and not making contact with the rubber piece in the head cap.

The cylinder has a spring that allows for movement up and down, take a pliers and gently pull up the cylinder if it does not move freely on its own. It will stop when it reaches the cylinder plate ( the part with 2 screw holes for easy removal). Be careful not to mar the cylinder though.

When reassembling the cylinder should make contact with the head cap. Hope that works!


1 Related Answer

Anonymous

  • 1244 Answers
  • Posted on Jan 21, 2010

SOURCE: Hitachi NV45AB coil nail gun is leaking air from

the top!! o-ring inside of thr top plate is bad you need to remove the plate /dissasemble and replace the o-ring

Ad

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1helpful
1answer

My Porter Cable FR350A Framing Nailer continually leaks air from exhaust port

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
0helpful
1answer
1helpful
1answer

Why does my Hitachi nv45ab gun double fire nails?

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
1helpful
1answer

Why won't feed plunger advance nails?

The two hex head screws on the very top of the head hold the air deflector and attach to the headvalve (the part inside the head with rubber coating, this headvalve has a gasket under that should be check for proper alignment ). Other small screws that look like set screw are only plugs that are removed to install auto control hoses in factory work. These are only plugs so just put them in a few turns with locktite.
1helpful
1answer

Hitachi NV45AB won't advance nails

This problem could be caused by the head gasket fliped the wrong way not sealing small hole in the body. Also the head valve gasket (small round gasket between headvalve and head) could be place with vent hole mis-aligned. Check these two items and post again.
0helpful
1answer

I have a N80SB stick nail gun that have been leaking air from the trigger valve but was still able to shoot nails. After 3 months of discontinued use, I plugged in the air hose and fire the first nail

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.
0helpful
1answer

I have N80 coil nailer not exact sure on what exact nail gun it is considered but it is leaking air out exhaust ports as soon as you hook air up to it and cylinder moves slow into the drive position like...

you are correct, also you want to look at the cylinder ring and also the bumpers. These tools are not that hard to rebuild. Make sure that you light grease all the o-rings before reassembly. If the bumpers (under the cylinder) are destroyed you would also need to remove any small fragments from the air tube that goes to the feed piston. Let me know if you need more assistance.
5helpful
1answer

AIR BLOWING OUT OF EXHAUST PORT DO NOT NAIL AT ALL

you have a problem with a split o ring or a seal that has gone bad. I would suggest buying a rebuild kit and redoing all the internal parts. It is not that hard to do and I would suggest taking some pics along the disassembly to make it easier when rebuilding. Let me know if you need more help.
0helpful
1answer

Hitachi nail gun,piston/nail push rod wont retract after pushing nail (stays protruding out of gun so the remaining nails stay underneath it

You have one or more worn o-rings in the head of the gun. They direct the air to the proper parts of the gun to first drive the nail then to return the driver to the top of the gun for the next nail. Depending on the manufacturer and your model number, some companies make kits to replace the o-rings (always replace all of them). For some companies you have to get a breakdown of the gun and order each o-ring seperately.
9helpful
2answers

Hitachi NV45AB coil nail gun is leaking air from top of gun

the top!! o-ring inside of thr top plate is bad you need to remove the plate /dissasemble and replace the o-ring
Not finding what you are looking for?

6,809 views

Ask a Question

Usually answered in minutes!

Top Hitachi Tools & Hardware - Others Experts

vince

Level 3 Expert

2530 Answers

Brad Brown

Level 3 Expert

19187 Answers

john h

Level 3 Expert

29494 Answers

Are you a Hitachi Tool and Hardware - Other Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...