Bostitch stapler T40S2 has air leak at trigger. I need repair instructions to replace orings

Most likely the orings or seals in the headvalve are not making perfect seal. Remove the head and pull out the headvalve. Apply plenty of white grease to orings and test again. If the gun fires, then will need oring kit soon, or just keep using plenty of grease. If the gun still does not fire, check that the safety foot is depressing the trigger valve all the way in. Good luck

Sounds like your gun needs servicing. normally strip, clean and usually fit new O rings to head valve assy, piston & usually sleeve.

If the new trigger valve leaks air when you connect the air supply, most likely defective valve or air is leaking past outer trigger valve orings due to debris in the slot or new orings were cut when the valve was pushed in. If air leaks when you depress safety to fire gun then most likely problem is in the head valve or safety foot is not pushing the firing pin all the way in. Easy test, remove nails and remove the trigger to expose the firing pin. Connect air and very quickly depress the firing pin all the way in. If the gun fires, adjust the safety foot as needed. If the gun does not fire, remove the head and check headvalve orings for good snug fit against the cylinder within the head. The surface were orings make contact must be very smooth and not too deeply worn. If you notice fine scratches remove with fine sandpaper. Reinstall head using plenty of white grease on all the orings within the head and retest. Good luck

This problem is caused by air leaking past orings in the head valve. Remove head and pull out the head valve. The metal surface on the head where oring makes contact should be smooth and oring should fit snugly. Of scratched or deep groove, or if oring is worn, the gun will not fire (sand with very fine paper or replace head). Also examine the headvalve where smaller oring makes contact. If small scratches are visible, remove with very fine paper or replace. To test if head valve is the problem, remove head and headvalve and apply plenty of white grease where orings make contact and replace head then test. If the gun fires, air was leaking past the orings. Good luck

Below the rubber bumper is the poppet actuator. The actuator has 3 screws that attached it to the actual poppet below. If the screws do not seat well and/ or if the gasket between these two parts is bad, air will leak out the top. Remove the poppet actuator to check oring on the actuator and the surface of the body of the gun where the oring makes contact. Look for damage to actuator or side wall and repair as needed (sand sidewall where oring makes contact with very fine sandpaper if scratched or dented). If oring does not fit snuggly against sidewall, use teflon tape below oring. Parts are available at www.bostitch.com.

Your nailer uses a trigger valve (could be part # tva6 cost about $20, need to look up) and is sold at www.bostitch.com or generic valves sold on ebay . If you have a source for orings, you could try to repair the valve. Remove the roll pin that holds the trigger to expose the tva6 valve. There are roll pin/pins that hold the valve in just above the valve in the body. Remove these pins and apply air pressure to gun to pop-out the valve. Use caution when you do this. Remove nails, lower pressure to gun and use glove or rag to catch valve because it could come out with force. With tva6 valve in hand remove two pins that hold valve together and remove inner plunger. The middle oring on plunger is cause of leak. Try using an oring about same size as the broken seat. It must fit pretty tight to work. If you had a small leak it could be that the firing pin orings fit too loose or just too worn. Use silicone lube or oring lube on the orings and the valve port. Good Luck on your repair and email if you have other questions

Your nailer uses a trigger valve (part # tva6 cost about $20) and is sold at www.bostitch.com or generic valves sold on ebay . If you have a source for orings, you could try to repair the valve. Remove the roll pin that holds the trigger to expose the tva6 valve. There are roll pin/pins that hold the valve in just above the valve in the body. Remove these pins and apply air pressure to gun to pop-out the valve. Use caution when you do this. Remove nails, lower pressure to gun and use glove or rag to catch valve because it could come out with force. With tva6 valve in hand remove two pins that hold valve together and remove inner plunger. The middle oring on plunger is cause of leak. Try using an oring about same size as the broken seat. It must fit pretty tight to work. If you had a small leak it could be that the firing pin orings fit too loose or  just too worn.  Use silicone lube or oring lube on the orings and the valve port. Good Luck on your repair and email if you have other questions.

Hi,
You need a new trigger valve TVA6.

Go to the Stanley Bostitch website. Click on schematics & parts. Find your model number in the drop down list. There is a list of parts and pricing. Just above the parts is a link for the schematic. Honestly, I worked on these things for years. It is best to replace the entire trigger valve. It comes as a kit with instructions grease, and a little tool to hammer your pins out. Lemme know if this helps. Please rate me

I have repaird hundreds of nail guns with a problem similar to yours. Depending on the brand and model, the problem can be repaired by checking the following. Headvalve orings should be checked for wear and any surface that the orings contact must be smooth and free from scratches. If the surfaces are scratched try to smooth with fine sandpaper and use light grease instead of oil when assembling. The safety contact foot may not be reaching high enough into the trigger to properly push in the trigger button. Check for worn spots on the trigger that may be filled in with epoxy, loose fitting trigger caused by worn roll pin or retaining pin. Some of the trigger valves as used on many bostitch nailers (tva6 valve) used a plastic pin which contacts the trigger. If this pin is loose or worn the valve should be replaced. Some tva6 valves have a vinyl looking sort of oring that fits too loose on the spool. This vinyl oring in not available by itself but if the oring fits too loose the gun will not fire and leak air. On bostitch remove the trigger and the rollpins holding the trigger valve and apply air to gun to eject valve. (use heavy glove to catch valve as it will come out with force)