# fixing dropped air stapler



## ratherbefishin' (Jun 16, 2007)

Sounds like the problem is in the piston/cylinder assembly. Could be a cracked sleeve, jammed piston, or could be as simple as a displaced seal.


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## wrangler (Oct 9, 2008)

Have you oiled it? Mine will do that occasionally, and 4-5 drops of oil into the air inlet usually solves the problem.


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## cwebber (Dec 30, 2008)

wrangler said:


> Have you oiled it? Mine will do that occasionally, and 4-5 drops of oil into the air inlet usually solves the problem.


Yes I applied liberal amounts of oil - that's the first thing I tired since it was the easiest


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## Termite (Apr 13, 2008)

Sometimes rapping the thing against a solid piece of wood will pop it back. Unfortunately, two Bostitch guns that I own have done the same thing and need to be repaired. I won't buy another Bostitch because of it.


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## cwebber (Dec 30, 2008)

ratherbefishin' said:


> Sounds like the problem is in the piston/cylinder assembly. Could be a cracked sleeve, jammed piston, or could be as simple as a displaced seal.


That makes sense. The piston and ring slide freely up/down clyinder, so I'll give the rest of that assembly a closer look and report back. 

Thanks


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## cwebber (Dec 30, 2008)

*Solution*

Thanks for the help. I finally fixed the gun so I thought I would post the solution here in case anyone else has the same issue.

I finally got a hold of another gun and started swapping parts in until I isolated the problem. It turns out there were no broken pieces in the gun, and no seals or O-rings noticeably out of place.

The problem was in the head valve assembly (right under the exhaust port above the cylinder). It is supposed to seal with the top of the cylinder and is held in place by a spring and the bumper/piston stop. When I took apart the head valve, re-greased everything, and put it back together the gun started working normally.

I think the spring that tensions the head valve got bumped out of place slightly in the drop so that it no longer formed a tight seal with the cylinder. Perhaps another hard bump would have also knocked it back in place (as was suggested above).

Many thanks,
chip


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## ironimaginings (Dec 25, 2010)

*Bostich air stapler repair*

Thanks for your post on servicing the head valve assembly of an air stapler. I had torn down my Bostich twice with no success and was about to give up when I saw the post. Now it's working fine and one less item in the landfill.


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