Air gushing out of classic

[Bosgarage57]

Hi guys. I just received a 68 classic in trades. Its my first mag. When I hook c02 up to it it gushes air down the barrel. Not a small leak but huge. I watched Tom kayes video on YouTube so I ordered a repair kit and should be here in a couple days. I was just wondering if there was something else I could check in the mean time? All the orings look good in a valve and on off as well.

[blackdeath1k]

First. Mags were never a fan of co2. So at all cost keep liquid co2 out of the valve. You will freeze Orings.

Now for your problem. Sounds like power tube oring at first glance. With air on does it still leak down the barrel when you hold the trigger pulled in?

Really. Unless you know how long ago the marker war rebuilt. Just replace all Orings and be done with it. That will most likely fix any issue that would come up for quite some time.

[Bosgarage57]

Gottcha. The guy i got it from said all the rings had been changed and I believe him. I will change all the rings and check the spacer when I get the kit. Holding in trigger has no effect on on it. It is going to a foregrip then back to the valve so it's not going straight from asa to valve.

I just hate to wait a week for parts to come in...arg!

[vintage]

take it apart and check the o rings, if they are white then they should still be good, if they are light yellow its pretty much the same, if they are dark then replace them. if they are buna than there is a chance one could be the wrong size. it could be a power tube spacer problem as well, if it has the copper spring inside the powertube you need to replace that with a spacer. mags love oil especially if they have been sitting awhile.

[Cyco-Dude]

if holding the trigger does nothing, then your issue is in the on/off top. check those two o-rings. the white teflon o-ring should sit inside the urethane powertube o-ring. also, it should be a snug fit around the on/off pin. if it slides freely, then it is too loose and should be replaced.

[blackdeath1k]

if holding the trigger does nothing, then your issue is in the on/off top. check those two o-rings. the white teflon o-ring should sit inside the urethane powertube o-ring. also, it should be a snug fit around the on/off pin. if it slides freely, then it is too loose and should be replaced.

Correct me if I'm wrong. Been a long time since using co2. But wasn't the on off Orings the ones that generally got froze?

I don't know how many times I had to rebuild my valve back in the 90s due to freezing the valve. That was actually why I converted to comp air back then.

[athomas]

I echo what Cyco-Dude is saying. If holding the trigger does nothing, then air is flowing past the on-off area, even with the pin in the closed position. That would indicate bad orings, wrong orings, or a missing oring. After that is fixed, if it still leaks out the front with the bolt in the reset position, then the powertube should be looked at.

[Bosgarage57]

So replaced all the orings and it's doing the same thing. But the trigger isn't resetting every time. I'm not sure what to do unless the spacer is not the right length.

[Cyco-Dude]

have you tried turning the velocity up? it still leaks from the barrel when you are holding the trigger?

[Bosgarage57]

How far should the rest but be turned in?

[Cyco-Dude]

How far should the rest but be turned in?
until it works, or it vents out of the back. it's going to do one of those two things lol!

[Bosgarage57]

It's more so still going out the barrel. I'm pretty sure I could put a fire out

[athomas]

Are you sure the on-off pin is installed in the correct orientation? Does it have one of the newer universal on-off top (same top and bottom) or the older one with the X cut into one side?

[Bosgarage57]

Yup. I like the fact they put a diagam on the valve itself. Its very helpful

[Cyco-Dude]

i would get a smaller power tube spacer. is the body polished? is the frame or field strip screw over-tightened? i usually just snug the frame screw up holding onto the small end of the allen wrench, and hand-tighten the field strip screw. this applies only if the leak stops when holding the trigger. if it still leaks when holding the trigger, you have not fixed the issue in the on/off top.

[cockerpunk]

one of the problems with co2 ive seen before is that a small leak becomes a really big leak because of the temperature drop when it expands freezing the oring prevent it from sealing. this makes the leak bigger, which causes more co2 expansion, and round and round we go.

id try and do your leak testing with compressed air until you get it solved, then if you have to, switch over to co2.

[Menace_AO]

OP,

It sounds as though a couple of things may be out of whack at the same time. Try the following:

1. Remove the valve/bolt assembly.
2. Look at the bolt and spring. The spring, when correctly installed, should extend beyond the bolt tip. If not, it is overly worn and may be too weak to properly reset the bolt.
3. Next, orient the valve so that the power tube is facing up, and install the bolt. It should easily slip over the power tube, and then stop short of the bottom and sort of 'float' above the blue washer/bumper. That tells you that the power tube o-ring is properly engaging the bolt stem. If it sits all the way flush, then take a nickel, unscrew the power tube tip, and see if there is either a copper spring or brass spacer down in there. It may be missing, causing the lack of seal, and thus, the leak.

4. Next, remove the on/off assembly, and remove the pin from the assembly. Inspect the pin. It should be machined and polished cleanly from end to end with no rough spots, gouges, or deep scratches. It also should have a hollow machined into one end, making it look like a ball. This side always faces the sear, and the square end should face the top o-rings in the valve. Next, set the on/off assembly on the table upside down and install the pin so that the ball end is up. When the pin makes contact with the table you should still be able to see the ball end exposed on the top.

Step #4 is to ensure that the the pin is in good order, i.e., (a) is the correct length to work with the sear to seal the valve [it may have been broken/filed down incorrectly] and (b) has not been installed upside down, which would prevent proper sealing when the trigger is pulled, and (c) has not become so damaged that it cannot seal in any case.

Good luck, and please keep us posted as to any other symptoms and, especially, what produced a fix.

[athomas]

Is the rail bushing installed?

[Bosgarage57]

Where would that be?

[Cyco-Dude]

Where would that be?

in the rail, towards the back. it's the 1/4" roll pin that locates the grip frame correctly.