BlackVCG's ULT Thread

[SOLITUDEbwk]

Ok, so new issue.... When I replaced the little black oring I had to push the stems back together.... I'm thinking I may have pushed them together too far, as there's no real "stop" when you push them back together. The stem is now not long enough to actuate the on/off... Does anyone know how far I need to compress this thing? "Until it fires" is not a significant answer for me.

[athomas]

Ok, so new issue.... When I replaced the little black oring I had to push the stems back together.... I'm thinking I may have pushed them together too far, as there's no real "stop" when you push them back together. The stem is now not long enough to actuate the on/off... Does anyone know how far I need to compress this thing? "Until it fires" is not a significant answer for me.

They will only go as far as needed. The stem of the small end will bottom out in the hole of the larger one.

What do you mean by "The stem is now not long enough to actuate the on/off"? Is the on-off remaining open when the mag is fired, causing the bolt to stick and air to rush out the front? If that is the case, remove some of the shims between the two halves to allow for a shorter pin length.

[SOLITUDEbwk]

What do you mean by "The stem is now not long enough to actuate the on/off"? Is the on-off remaining open when the mag is fired, causing the bolt to stick and air to rush out the front? If that is the case, remove some of the shims between the two halves to allow for a shorter pin length.

Well, I pulled it all apart again to check the length with a caliper and it's within tolerance. I just can't get it to fire. No leaks what-so-ever. The trigger rod pushes forward to 1mm from the trigger.

I'll pull the trigger and can feel the air pressure. The sear just isn't releasing the bolt allowing it to fire.

The velocity is turned up farther than it probably should, I've turned it all the way up and all the way down. No change.

There is a steady 850psi set on the regulator and I've tested it on another marker.

I've taken it apart to see if the bolt is sticking, nope, smooth as ever.

I've relubed every oring in the valve and there are no leaks.

I've tried removing and adding shims on both the ULT and LVL10. The power tube tip has a <0.5mm nick on the tip protruding toward the bolt, but it's fired before without issue.

I'm stumped. The only thing I've changed was rebuild the ULT. Help!

[athomas]

Well, I pulled it all apart again to check the length with a caliper and it's within tolerance. I just can't get it to fire. No leaks what-so-ever. The trigger rod pushes forward to 1mm from the trigger.

I'll pull the trigger and can feel the air pressure. The sear just isn't releasing the bolt allowing it to fire.

The velocity is turned up farther than it probably should, I've turned it all the way up and all the way down. No change.

There is a steady 850psi set on the regulator and I've tested it on another marker.

I've taken it apart to see if the bolt is sticking, nope, smooth as ever.

I've relubed every oring in the valve and there are no leaks.

I've tried removing and adding shims on both the ULT and LVL10. The power tube tip has a <0.5mm nick on the tip protruding toward the bolt, but it's fired before without issue.

I'm stumped. The only thing I've changed was rebuild the ULT. Help!

Install the valve without the bolt. Hold the trigger in when you air up the valve. Gently release the trigger and see if air is released. That will tell you if the on-off is opening and closing properly and we can go from there. Make a note of where the trigger is when the air starts and stops flowing. Then check the sear position in the body with the trigger and sear in that position. It will help you determine if the sear is in the proper position to lock/release the bolt when the on-off is open or closed.

[SOLITUDEbwk]

Install the valve without the bolt. Hold the trigger in when you air up the valve. Gently release the trigger and see if air is released. That will tell you if the on-off is opening and closing properly and we can go from there. Make a note of where the trigger is when the air starts and stops flowing. Then check the sear position in the body with the trigger and sear in that position. It will help you determine if the sear is in the proper position to lock/release the bolt when the on-off is open or closed.

I'll give it a "shot" when I get to the house tonight. It's like the on/off isn't opening to release the pressure. And the more I look at this diagram I'm almost certain the stem is compressed too short on the on/off. Does anyone know what the length should be?

[SOLITUDEbwk]

So, I was able to pull it all back apart. Pulled the bolt out entirely. Held down the trigger while I gassed it up. Let off the trigger slowly...... It still didn't fire. So we've narrowed the issue down to the on/off.... Thoughts? The on/off is freshly rebuilt. It looks like I'm back to my "Stem length" question.

[athomas]

So, I was able to pull it all back apart. Pulled the bolt out entirely. Held down the trigger while I gassed it up. Let off the trigger slowly...... It still didn't fire. So we've narrowed the issue down to the on/off.... Thoughts? The on/off is freshly rebuilt. It looks like I'm back to my "Stem length" question.

It means the on-off pin length is too long and the top sealing edge of the pin is not moving below the sealing edge of the top oring. Adding more ULT shims will push the top section and oring up farther so that the sealing edge of the top oring is farther away, similar to installing a shorter pin.

[SOLITUDEbwk]

It means the on-off pin length is too long and the top sealing edge of the pin is not moving below the sealing edge of the top oring. Adding more ULT shims will push the top section and oring up farther so that the sealing edge of the top oring is farther away, similar to installing a shorter pin.

Ok, so after pulling it apart several times and measuring, I've found that I didn't have the stem compressed enough on the On/Off, that and I had a 1 too many shims not allowing the stem to seal on the top oring when I pulled the trigger....

So, now I can get the gun to fire, but something inside the valve is getting stuck. It takes several seconds between shots for the marker to recharge. I've tested multiple HP tanks to see if it was the regulator, but I'm still getting the same results. Anyone have any insight?

[athomas]

So, now I can get the gun to fire, but something inside the valve is getting stuck. It takes several seconds between shots for the marker to recharge. I've tested multiple HP tanks to see if it was the regulator, but I'm still getting the same results. Anyone have any insight?

It now sounds like your level 10 is getting bolt stick and needs tuning. Try the next larger carrier size.

[splashkitsrock420]

we need an update on this i think ...... pix wont load and links r dead ...maybe its just me ..lmk pls ...in need of fixing a few ult pins,,,,, started here for info

[Scottprocurot]

Replacing o ring in ULT

Ok so I have read all the response
I will need to replace the little o ring on the pin
Do I just push it on
I have read something about lock tight
Do I need to reassemble with it
Help before I start
Thanks

[Tunaman]

No need to take the pin apart. Cut the old one off using a razor blade. Do not scratch the pin...do not bend the pin. You can force the new oring over the pin. It will go right on.

[Zone Drifter]

No need to take the pin apart. Cut the old one off using a razor blade. Do not scratch the pin...do not bend the pin. You can force the new oring over the pin. It will go right on.

I need to replace mine as well. So the small black o-ring will fit over the pin? I didn't want to mess up that thin pin or the new packing, just making sure that is the best way to replace that little o-ring.