milled ReTro Valve not firing with ULT on/off

[Tachiro]

So I just got my Retro valve back from Luke's http://s10.postimg.org/eoosxmbbd/2014_09_28.gif.

The ULT fits the valve now, but it doesn't seem to fire anymore. I'm just going to pour all the specs and testing i've done so far in no particular order:

- Mostly stock/classic setup except for the valve/ULT
- Tank pressure: ~2000psi
- Tank output: little under 900psi
- pushing the sear back with a screw driver doesn't work either
- The ULT fits the valve up until about 4-5 shims. After that, it's too tall to clear the body when i put the valve back in.
- I tried the ULT with 0 shims and got nothing
- I have an RT on/off that shoots fine with the valve (no leaks either)
- i'm using this kind of sear 92288 btw
- I'm not sure what role/potential role these lvl 10 powertube spacer things(?) play, but i'm using the original one it came with

I think that is about all the troubleshooting/testing i can come up with at the moment. Could this mean i may need to file the pin down?

[Tunaman]

So I just got my Retro valve back from Luke's http://s10.postimg.org/eoosxmbbd/2014_09_28.gif.

The ULT fits the valve now, but it doesn't seem to fire anymore. I'm just going to pour all the specs and testing i've done so far in no particular order:

- Mostly stock/classic setup except for the valve/ULT
- Tank pressure: ~2000psi
- Tank output: little under 900psi
- pushing the sear back with a screw driver doesn't work either
- The ULT fits the valve up until about 4-5 shims. After that, it's too tall to clear the body when i put the valve back in.
- I tried the ULT with 0 shims and got nothing
- I have an RT on/off that shoots fine with the valve (no leaks either)
- i'm using this kind of sear 92288 btw
- I'm not sure what role/potential role these lvl 10 powertube spacer things(?) play, but i'm using the original one it came with

I think that is about all the troubleshooting/testing i can come up with at the moment. Could this mean i may need to file the pin down?Measure the ULT Pin. It should be .740. Make sure the pin is not bent. If the valve works fine with another on/off then the problem is in the ULT. That is a REALLY old sear. You should change it. Make sure the trigger rod is not hitting the back of the trigger when gassed up. Let us know.

[Tachiro]

looks like the pin measures .750 on this digital caliper i have here. Pin looks straight as far as i can tell. lol oh and that sear was from an image search (one of bacci's antiques); I was trying to show the nature of the shape of the one i have. i guess it's the design they had before they got rid of that excess metal toward the lower front. I'll take another look at the trigger rod.

[Tachiro]

just adjusted the trigger rod. It definitely was hitting the back of the trigger gassed up. Still doesn't fire, but at least that's been adjusted . I have another sear i can try from another setup (it's the newer kind).
Btw, the pin length in the RT on/off i used is .740 if that helps. I can take some pics too.

[luke]

I know you said you adjusted the trigger rod but did you leave a gap between the rod end and the back of the trigger when gassed up?

[Tachiro]

I know you said you adjusted the trigger rod but did you leave a gap between the rod end and the back of the trigger when gassed up?

it's a very thin gap, maybe a page or two could fit between the rod and the back of the trigger.

[Laku]

Should be about credit card thickness.

[luke]

it's a very thin gap, maybe a page or two could fit between the rod and the back of the trigger.

Like Laku indicated, that it not enough. You need around .030" for the on/off to operate properly.

[Tunaman]

It doesnt matter how big the gap is...as long as it doesnt touch the trigger when gassed up.

[Tachiro]

Update: so i just got around to adjusting the trigger rod again. Yup doesn't touch the trigger when gassed up. And to be specific, it's a gap about as thick as a credit card now.

92299

Though i will also note that i've been gassing it up and frequently testing it throughout this whole adjusting issue and can't say it has ever fired since i put the ULT in.

[Laku]

That sear looks really odd where the rod clavicle attaches. The clavicle should be at the bottom of the sear "leg?". See picture below.

edit. But I guess that's normal for those old style sears?

http://cdn.shopify.com/s/files/1/0555/5573/products/agd_automagminimag_sear_assembly_1024x1024.jpeg

[Cyco-Dude]

Update: so i just got around to adjusting the trigger rod again. Yup doesn't touch the trigger when gassed up. And to be specific, it's a gap about as thick as a credit card now.

Though i will also note that i've been gassing it up and frequently testing it throughout this whole adjusting issue and can't say it has ever fired since i put the ULT in.
how many shims does it have in the ult? if there aren't enough, the gun will not fire. i'd start at two and go up from there and see what it does, if you haven't already.


That sear looks really odd where the rod clavicle attaches. The clavicle should be at the bottom of the sear "leg?". See picture below.

edit. But I guess that's normal for those old style sears?
yeah, it's just the older version sear.

[Tachiro]

Just bought a new sear from ANS (man they've really come a long way since the days of explosive shipping fees for anything).

So.. I must say in the meantime i'm completely stumped as far as what i could possibly do to get this back to firing.




how many shims does it have in the ult? if there aren't enough, the gun will not fire. i'd start at two and go up from there and see what it does, if you haven't already.

i believe there's about 4 shims in there at the moment. I was mentioning earlier that i don't think i can go over 5 shims or else it won't clear the body when i put the valve back in.

[rawbutter]

If everything works with an RT on/off but not with the ULT on/off, the problem has to be connected to the ULT pin length (assuming there are no other leaks). Personally it sounds to me like the pin is too short, not too long, so when you're pulling the trigger, the sear isn't pushing the pin far enough up to release the air from the regulator.

But let's check a few other things first before you go and buy another pin.

1. Make sure you're not adding so many shims that you have to force the valve into the body. If you do that, you can mess up the alignment/tolerances. The bolt will press against the inside of the body and not move forward when you pull the trigger.

2. Make sure you don't have any extra o-rings inside the on/off hole. Someone will correct me if I'm wrong about this, but I seem to remember that the RT on/off has two "extra" o-rings on top, but the ULT doesn't. So if you left those o-rings inside, that would drastically increase the height of the on/off, meaning it won't fire when the trigger is pulled (because the pin can't move far enough).

This is an RT on/off...
http://i279.photobucket.com/albums/kk156/Mimical/DSC08013.jpg

And this is a ULT...
http://i279.photobucket.com/albums/kk156/Mimical/DSC02685.jpg

Note the extra o-rings at the top of the RT. Sometimes those get stuck inside the body when you're pulling the on/off out. Maybe that's the simple fix?

[Tunaman]

If everything works with an RT on/off but not with the ULT on/off, the problem has to be connected to the ULT pin length (assuming there are no other leaks). Personally it sounds to me like the pin is too short, not too long, so when you're pulling the trigger, the sear isn't pushing the pin far enough up to release the air from the regulator.

But let's check a few other things first before you go and buy another pin.

1. Make sure you're not adding so many shims that you have to force the valve into the body. If you do that, you can mess up the alignment/tolerances. The bolt will press against the inside of the body and not move forward when you pull the trigger.

2. Make sure you don't have any extra o-rings inside the on/off hole. Someone will correct me if I'm wrong about this, but I seem to remember that the RT on/off has two "extra" o-rings on top, but the ULT doesn't. So if you left those o-rings inside, that would drastically increase the height of the on/off, meaning it won't fire when the trigger is pulled (because the pin can't move far enough).

This is an RT on/off...
http://i279.photobucket.com/albums/kk156/Mimical/DSC08013.jpg

And this is a ULT...
http://i279.photobucket.com/albums/kk156/Mimical/DSC02685.jpg

Note the extra o-rings at the top of the RT. Sometimes those get stuck inside the body when you're pulling the on/off out. Maybe that's the simple fix?If the oring was still in there he wouldnt be able to get the ULT in...

[Tachiro]

- It seems like none of the shim amounts between 1-5 have made any difference here.

- i checked the ULT, looks like it's just the ULT in there. no extra orings or anything in the valve.


So onto some of the latest tests:

I took the bolt out and aired it up with the trigger held. No leak or anything. Then i let go of the trigger and a burst of air escaped (i cut off the tank air so i don't waste it, but i'm assuming it would just continue).

Now i put the bolt in without the spring and aired up with the trigger held. No leaking. Then i let go of the trigger and heard a soft but constant leak. I pull the trigger and it fired once.

[Tachiro]

test updates:

- Not sure if this matters, but i was also able to try and put the whole mag together without the body, which was quite interesting. I stuck my thumb behind the bolt to push it forward so that i can see how it engages the sear. When i pull the trigger, the release point seemed a bit late so i moved the trigger rod forward.
Now it releases somewhere around halfway through the pull. I gassed it up and that didn't make a difference though. Still won't fire.

- I also realized i don't have enough shims. I figured i could try and put all the shims in the bolt to see what happens. Even though it didn't fire, I'm seeing that regardless, i also made a drastic change at the same time by putting the ULT in with no shims at all.

- Now i'm considering buying a new ULT to see if there might've been some detail about this ULT that was too subtle for me to catch during this whole saga.

[athomas]

Try this:

Install the valve without a bolt or bolt spring installed. Hold the trigger and gas it up. As long as you hold the trigger, it shouldn't leak. If it does, then there is a leak past the on-off, which isn't one of your problems. Gently release the trigger until it leaks out the powertube. You can control the air flow by holding or releasing the trigger. It will give you and idea of where in the trigger pull the on-off actually opens and closes, if it opens at all.