This gun has a seal at the bottom of the piston which is about 2 1'' in diameter. the old seal was wax and was probably installed by heating it. the new seal is nylon. since this seal must pass over a lip that exceeds its diameter, do I heat this ''nylon'' seal or do I physically
stretch it to install it.
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Re: SENCO SN-IV LB3500 Seal leaks air
The old seal was origionally the same as the new one, a white nylon, however over time the seal breaks down and looks like hard wax. The new seal may be installed by heating with hot air gun till plyable and gently streach over lip. While the gun is open, lube with nail gun oil. the piston should not slide down the cylinder under its own weight, if it does, replace the piston oring. Diagram available at senco.com
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There are 4 main causes usually with this tool:
1) Check the seal in the bottom of the cylinder (under the bumper) #BF0070 (#12 on the breakdown) If this seal is missing or worn the piston will not always return fully.
2) The pusher spring #GD0253 in the magazine is not moving the nails forward
2) The driver is bent or the tip is worn / chipped
3) The check valve ring #LB0077 on the cylinder is not sealing properly
Let me know if this helps Senco SFN30 15 Ga Finish Nailer Parts
Several things to check. Piston ring /oring should not be too tight or too loose. Should be easy to push driver back up but not so easy that it drops back down if no nails in gun. If piston /oring ok then check for air leaking past driver seal at the nose of the gun. If there is too much gap between the driver blade and lower seal, air pressure will be lost down the nose of the gun. Finally, check if your nailer has a check band or oring check around the cylinder covering a series of pin holes (usually found on the lower part of the cylinder). This check band causes the driver to be pushed up with force. Good luck
First get an exploded view of gun and parts list and numbers from senco.com,,take nail gun apart,,,take a good look at the rubber bumper stop to see if it is broken,,look at the driver nut to see if it is tight,,,,you can go to juldan.com once you have gotten a list of the worn parts,,,juldan sells complete o ring kits along with nearly all parts needed for your repair
Some reasons the driver/piston assembly won't retract fully: - damage to the o-ring (LB1003) around the piston - cylinder (BA0165) is scored badly - driver (EA0167) is bent, twisted or warped - o-ring (LB1023) around bottom of cylinder (in groves & covering small holes) is stretched out or out of place. - Seal (BC0492) at bottom of cylinder & under bumper is damaged or gone
May need cylinder seal # bc0438. When this seal fits loose or is cracked, air will leak past and push piston down to bottom of the cylinder. If the seal fits snuggly and looks in good order, suspect headvalve orings and cylinder spacer orings leaking. Order oring kit and seal. Use silicone paste lube on all the orings. Look carefully at the surfaces where orings make contact and remove scratches with 300 grit sandpaper(fine scratches will allow air to leak past new orings). To make the gun work with poor fitting orings. Clean inside of gun with diesel and apply plenty of silicone paste to orings (using same orings if not cut or broken). If gun works as normal, the silicone paste is temporarly sealing the orings. It may continue to work for a while untill you get new parts. Good luck with repair.
Air leaking thru nozzle (where nail exits ) can be caused by two issues. Air leaking past valve rubber at top of cylinder where headvalve seals when under pressure. If leaking at valve rubber seal the piston will usually be pushed down if there are no nails in gun. If the driver stays up while leaking then problem is at cylinder plate. This plate has two orings that seal air pressure. On seals against the body of gun and the other seals against cylinder. Leaks can occur if body of gun is worn, warped or has scratches where oring makes contact. Also look closely at the plate for crackes. Replace parts as needed. Good luck
You have worn or broked o-rings/seals inside the gun. The Finish Pro 32 is one of Senco's older guns and they no longer offer a repair kit for this gun. You have to go to a site like www.senco.com or www.ereplacementparts.com, find a breakdown of your gun and order each part you need. If you are going to rebuild the gun order all the o-rings/seals (Senco parts that start with LB) and any other parts that may be damaged like the piston stop, springs, etc. Lubricate the o-rings with light grease as you put them in and make sure to oil the gun regularly when you are using it to make your work last.
The feed pawl is moved by a piston that extends from a cylinder on the lower side of the guide body. There are a couple seals inside the cylinder that if damaged will not hold enough air to activate the piston and advance the next nail. The two seals are Senco part number LB0828 & LB0845. Better yet get a Senco YK0369 repair kit and replace all of your o-rings, you'll have a like new gun for around $60.
I think that you are referring to the firing valve and no it should not be split. I suggest going to Senco.com and typing in your model number fora breakdown for this tool. They offer different kits for various failures. Let me know if you need more help