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Bostitch T31 air leak thru small head hole

I had this rebuilt by a shop, then put a kit in it myself after it fired one brad and re-leaked. I only opened the head portion, not the handle section.

The leak is through the small hole in the head and only occurs when the trigger is not pulled, plus the gun does not fire. The plastic trigger does not appear bent and the gun has only seen light home use.

The new small O-ring seems to bind, unlike the old one and none of the old rings or seals seemed to be worn or leaking.

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I have repaired hundreds of nailers, however not a t31. I can offer you a few tips on general nail gun repair pertaining to leaks. It is important to check each oring separately if you can to check for proper fit/contact. Do not just replace all orings and then hope for the best. Each oring must fit snugly not too tight not too loose. The surface where the oring contacts must not have fine scratches. Inspect all surfaces with magnify lens for scratches and remove with fine sandpaper. Check each oring for nicks Make sure that gaskets do not block small ports that direct air to headalve. Use silicone grease instead of oil on orings and metal/plastic parts. Lowes sells a small container of silicone grease in the plumbing department. It is used to lube faucet parts. Oil will wash away too fast and sometimes it will swell the orings causing gun to jamb. Finally do not use too much pressure on small nailguns. Try using 70 to 90 lbs. Good luck

Posted on Dec 02, 2008


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