X-Valve, slight leak; can't find it

[jctam]

I have an X-Valve with a ULT on/off. When I gas it up it has a small kinda bubbling sound coming from the back. Its not coming from the velocity adj. If I put my ear right where the 2 reg body halves come apart I can hear it real good. It isn't that loud and It can keep 900 PSI overnight if I keep it gassed. If I hold the trigger back, it sorta stops, and when I let go it leaks more. I have replaced the on/off o-ring but not the 2 orings that keep the on/off snug inside the body; do thoes hold pressure?

[Dayspring]

If the leak stops when you hold the trigger, it's not the on/off orings.

My guess is that the reg-pin is either breaking in or needs replacing.

[toymyster]

Also it might be your power tube o-ring!!! Go down one carrier size and see if it will stop!! Hope this helps!!

[jctam]

The reg pin is breaking? How, its only like a week old! And no, its not the power tube o-ring.

[Eatem Alive]

i 've found that tightening or loosening the thumb screw fixes leaks also.

[eightball]

i think u tightened the thumb screw too much, too much pressure, so it leaks out the back..
happened with my mag too, i just loosened it and it stopped

[Dayspring]

[jctam]

Its still leakin' Tighter looser... it doesn't matter. But it makes it rapid fire more when its loose

[Dayspring]

That's cuz you're increasing the space between the on/off oring and the sear, so in essence, shortening the on/off pin.

Its still leakin' Tighter looser... it doesn't matter. But it makes it rapid fire more when its loose

[jctam]

What about the leak???

[jctam]

I have also replaced the Reg body o-ring... it still leak.

[Carbon Blue]

check your regulator piston oring.

[jctam]

Just changed the reg-piston o-ring... still leaking. What could it be? What could it be? It is leaking out the back but not out the velocity adj. Its hard to explain, if I put my ear on the X, its real audible. It sounds like bubbling, like a put put put sound. HELP!!!

[jctam]

ok, I took out the reg pin and oiled it up and now its gone. Thanks guys

[Mechanic79]

Similar type leak

I have an X Valve RT ULE with ULT.

The leak seems to be coming from the seam where the valve meets the ULE body.
I replaced all the o-rings on the ULT except the tiny black one, I replaced the small regulator o-ring as well. still the hiss.

When I pull the trigger and hold it, the hiss goes away. let off the trigger and it's back again.

I also tried loosening the field strip screw and VIOLA, the leak stopped but now the guns shoots like crap, bouncing and chuffing, retighten the screw and it shoots fine but leaks.

I use KC Trouble Free oil as well, oiled every part individually AND put 3 drops in the asa. I shot 50 shots with no luck.

What should I try next? Any insight would be appreciated.

Mechanic79