I have a Senco SN70 that has a very small but annoying leak in firing valve,,,know it is the firing valve because I put another unit in from another nailer and the leak stopped,,,all o rings and seals have been replaced with genuine Senco products,,any ideas on where to specifically look for leak! Thanks for your help!
Yes, the leak is most certainly due to damaged/dry-rotted o-ring seals in the firing mechanism itself, which would be the firing "valve" in Senco nailers.
Attached is the manual for the SN70XP model, which is virtually the same. Hopefully the trouble-shooting guide gives you some pointers.
But you'll most likely need to replace all of the seals on the firing valve, there are quite a few smaller o-rings on the valve. Once you clean the gun thoroughly then lube all o-rings up, the gun should be in tip-top shape.
I did replace every single seal and oring from a Senco rebuild kit,used the tube of Senco furnished lube,,,still has the small leak,,anyway I do have a spare!
If you already replaced the seals and o-rings with OEM parts and it still leaks, I'd recommend contacting a Senco service rep directly at 800-543-4596.
This is the best option from here. You could have a worn Head Valve or Cylinder as well.
Once you find the solution (I'm sure you will!) feel free to post it on this page!
