ULT Input Pressure

[El Zilcho]

Is it possible to have too great an input pressure when using an ULT? I ask because I have had a stubborn ULT leak that I can't resolve. I have pulled all of the shims out of the level 10, sized it so that it is one carrier down from the one that leaked and am using the shortest spring. The ULT randomly leaks both when the trigger is held down and when it is not. I am using a Ninja SHP which I believe is putting out about 1100 PSI. I can't seem to figure it out and it is irritating the heck out of me.

[Ando]

You positive it's leaking from the ULT? Holding the trigger down and see if it continues to leak.

[El Zilcho]

I am almost positive it's the ULT, like I said, with no shims, I adjusted the Level 10 carriers until it leaked and then backed down one size, I did that twice actually with two different 0-rings; so I am pretty sure it's not a leak caused by a bolt issue. I didn't mention previously but when I apply pressure to the valve or the 90* elbow the leak will either change pitch or stop. I have also tried adjusting the field strip screw, I have tried it both relatively loose and relatively tight with no change in result.

[Ando]

Your rail bushing installed?

Hold the trigger down when aired up. Is it still leaking?

[El Zilcho]

The Rail Bushing is installed but I don't have any air to trouble shoot with. I will try to figure it out next time I have air.

[athomas]

How old is your sear? How many shots have been fired with it?

[El Zilcho]

Not a ton of shots fired, less than 15 cases total

[athomas]

The sear shouldn't have any significant wear with only that many shots on it.

If it is leaking out the front and the bolt is reset, then the leak is caused by the powertube orings, not the ULT.

If its leaking out the ULT, then its the tiny black oring inside the ULT assembly or the larger oring around the bottom section of the assembly.

If it is leaking out the front caused by bolt stick, then it is most likely a level 10 issue unless the level 10 has been tuned and bolt stick still occurs. Then, the bolt stick and leak is most likely one of the two ULT top orings, or you have too many shims in the ULT. The top orings affected are the small one in the top, or the larger one around the outside of the top.

[El Zilcho]

The only ULT o-ring that I have not replaced is the tiny black one, I was not even sure if it could be replaced. I don't think I have one in my AGD o-ring kit. I will check again. Part of the reason why this is so frustrating is that I have read a ton of threads regarding this issue and all of the fixes I have read about and tried have not worked. I will keep plugging away. Thanks for your help.

[athomas]

Where specifically is it leaking? When it is leaking, is the bolt fully reset and the trigger pressurized?

[El Zilcho]

I don't have any air right now, I will have to put this thread on hold for the time being. It is hard to go from memory because the leak seemed to be inconsistent, so I don't recall a specific sequence of events. I can say that it leaked both when the trigger was held and not held and it did not sound like it was leaking down the barrel. The leak would appear more often after rapid firing (especially RT'ing). I will say this though, I could move the bolt a bit and when I did I could hear a slight clicking noise and the leak would stop. I intially thought it was level 10 related but then thought that maybe it had to do with the position of the on/off. When I say the bolt move I mean literally 1/64". Like I said though I am going from memory. Instead of wasting peoples time, I will get some air and write down the details as I tune.

I followed the level 10 set up instructions and can't go to the next carrier up because I get a very obvious leak, I don't have any level 10 shims in while this is happening

[Ando]

Well sound like your lvl 10 is tuned. When you do get air, replace your bolt spring.

From the sound of it, could be a worn spring and not the on/off.

[athomas]

I can say that it leaked both when the trigger was held and not held and it did not sound like it was leaking down the barrel. The leak would appear more often after rapid firing (especially RT'ing). I will say this though, I could move the bolt a bit and when I did I could hear a slight clicking noise and the leak would stop. The click is the sear resetting when the bolt is manually reset. That is a bolt stick issue. It could be a worn bolt spring as mentioned. It does sound like you have the correct carrier installed, so that shouldn't be causing any problems. When you hold the trigger and the leak continues, how long does it last? Sometimes, this leak will dissipate after a couple of seconds when the trigger is held. It is due to the lower pressure in the chamber after a shot not applying enough force to the oring to seal it right away. How many shims are installed in the ULT? Too many shims can cause a bit of leaking past the top one which will stop the bolt from resetting properly. Usually, this is accompanied by some erratic trigger reactivity though.

[El Zilcho]

So I am at my wits end, let me tell you why.

I tuned my level 10 so that it is one carrier down from the one that leaked and left all of the shims out.
The bolt was not resetting correctly so I was getting a small leak (I think it is from the ULT but I am not sure that makes sense, I listened down the barrel and it did not sound like it was coming from there).
I would stick my finger down the breach and push the bolt back (less than a 1/16" movement) and the leak would stop.
All this was occurring with the middle spring so using my quick goat thinking, I switched to the red spring thinking that the increased force would force the bolt back.
The marker would not fire with the red spring so I cranked up the velocity until the it started to fire.
Everything seemed fine but eventually the bolt started to stick again, again I could stick my finger down the breach and push the bolt back when it did stick.

The bolt would not reset if I short stroked the trigger (is that the correct term?)

The leak would start if I put a tiny amount of pressure on the trigger and then as you would expect when I pulled the trigger all the way the gun would not fire correctly.

What else can I do to get the bolt to reset correctly?

I don't think that my sear has that many cycles on it but that is the only thing I can think of.

My ULT has 3 or 4 shims in it and it barely RT's with 1000 psi input pressure, so I think that is setup correctly.

Please excuse the annoying amount of information.

[athomas]

Your information is excellent. It makes it easy to understand the problem.

It does sound like you are getting bolt stick. But it also sounds like you did get it tuned properly. The slight leak when you start to pull the trigger means your bolt is farther forward than it should be. This is usually an indication of a worn sear or too many shims installed. However, due to the number shots on your sear and the fact that you have removed all the shims, that shouldn't be the case.

Try a different white powertube carrier oring and go through the level 10 tuning process again. Perhaps your oring has a flaw.

You can check your sear by looking at the tip where it holds the bolt. If there is noticeable wear (if you can see a slight indentation where the bolt sits) then it is probably your culprit. It would be rare for it to be a problem with so few shots on it.

Short stroking is when you don't fully release the trigger before you pull it again for the next shot. The front chamber doesn't get a chance to fully charge before the next shot is fired, so that shot is usually a low velocity shot. In a mag with a level 10, there may not be enough pressure to push the bolt forward or maybe just enough to cause a chuff. It should always reset following any attempted shot because some of the air that pushed the bolt forward is vented out to allow the spring to push the bolt back into the reset position.

[dazbag]

I had absolutly the same issue. But! Not from the beginning. AND! I have a spydermag. Which already means, that i have to use a ult, to use it.
At the beginning, i was playing it, with the SHP 1100psi regulator, without issues. But after a while it started with bolt stick problems etc. I couldnt figure it out. changed everything on the ult, tried every possible way to adjust the ult.
But it got worse. It started, even not to shot. Then, it freaking started to leak really badly through the ult. Whatever i did, it didnt work.
Finally i just thought. Damn, it all started with this shp regulator. Changed the tank with a regulator that has about 850psi output. TATA, it works again!
I dont know why that is so, but with 850psi it just works. With 1100psi bad leak all the time. All orings fine. lvl10 tuned well!!
Try that, try a diffrent tank with lower psi output.
By the way. I love the SHP regulator. Using it on a cyborg rx without issues and on other automags as well. Well mechanical automags with stock on/off. Ripping 22bps with xvalve.

regards from germany! =), hope i could help you

[El Zilcho]

To rule out the Level 10 as the issue, couldn't I just stick it in my classic valve with the same carrier/o-ring combo and see what happens? Seems like if it does not leak then the ULT would have to be the issue. Any flaws in that rationale?

[athomas]

To rule out the Level 10 as the issue, couldn't I just stick it in my classic valve with the same carrier/o-ring combo and see what happens? Seems like if it does not leak then the ULT would have to be the issue. Any flaws in that rationale?Or you could put the classic on-off assembly into the X-valve and try it. That way you are still working with the same valve and replacing one of the suspect assemblies with a known working assembly. If it still occurs, you know it is level 10 related.