I bought the RN46 a new trigger valve this winter, finally got around to working on it for the season and it still won't fire.

I replaced the TVA6 valve, followed the instructions, everything went good. Before replacing it had a leak around the valve continuously when connected to air. Now when i connect it to air there is no leak but when you press it down on the work surface and pull the trigger it just dumps air out around the trigger. Release the trigger the air stops. So the valve appears to be working but for some reason the gun isn't firing.

The only other thing i noticed comparing it to the parts diagrams is the compression spring on the trigger, part number 100387 is missing. It was like that when i got it and never really noticed it again until now that the trigger doesn't stay down on its own and just flops up and down, but it always worked until the slow leak around the trigger valve developed.

Any ideas what might be wrong? I am going to order the compression spring but i don't think thats why it won't fire its more of a safety to keep the trigger down from the firing pin.

Why would it dump air around and out of the trigger when the trigger is pulled but not fired? I followed the instructions i could find online to tear it down, inspected the piston and bore and o-rings, everything looked good and was well lubricated inside and everything moves as it should, etc. Its just like the trigger valve is defective and not blowing air up into the cylinder??

Thanks!

The head valve assembly is quite clean not a spec in there, well oiled, but i guess the o-rings could be worn. Its had a couple boxes of coils through it by now.

If i push the piston down by hand with the head off and then put my hand over the cylinder and try to push the piston back up by pushing on the bottom end of the driver i can barely move it from the compression, the piston is well sealed. So the only thing i think it could be is the head valve assembly but couldnt hurt to replace the piston o-ring as long as its apart anyway.

Does MTR have the o-ring kit for the RN46? I couldn't find it on the site. I don't need a rebuild kit all the parts are like new in it, even the plastic head valve parts don't have any noticeable wear on them.

Oh and i checked the model again, its an RN46-1 nailer.

I found the page with the parts diagram and ordered the o-rings for the head valve as well as the seal for the top and the seal that goes on the bottom side of the valve, the one that seals to the top of the cylinder, i also ordered an o-ring for the piston and that pesky spring for the trigger.

That should finish my rebuild!

The trigger isn't leaking anymore at least, so i'm pretty confident that cleaning and replacing the o-rings should fix the rest of the problem.