[Solved] leak down barrel

[astr0xz0mbie]

hey was shooting my mag today and have a slight hissing leak down the barrel that stops when i hold the trigger down a bit. what causes this leak and how can i fix it. can someone give me detailed instructions or pictures on how to do this ? thanks guys

[MAGgot]

Replace the powertube o-ring. If that doesn't do it, put in a smaller powertube spacer.

[MAGgot]

http://www.otterpaintball.com/wp-content/uploads/2012/07/Air-Gun-Designs-Automag-Manual.pdf

[astr0xz0mbie]

which o-ring ? there is two one on the power tube tip and i see one below the carrier or spacer whatever you call it

[astr0xz0mbie]

leak only really happened when i switched springs, went from the long grey spring to short gold spring, could that have something to do with it ? checked the orings and they looked fine. changed them and the leak was worse then switched them back to the old orings and long grey spring, now there is no leak....wtf just happend ? lol

[Cyco-Dude]

which o-ring ? there is two one on the power tube tip and i see one below the carrier or spacer whatever you call it

the o-ring on the power tube tip is just to keep the tip from rotating loose. you shouldn't have to replace it, unless it rots off. the o-ring you're interested in is under the spacer (or spring, if it's a really old mag) if it's a lvl 7, or in the brass carrier if it's a lvl 10.

leak only really happened when i switched springs, went from the long grey spring to short gold spring, could that have something to do with it ? checked the orings and they looked fine. changed them and the leak was worse then switched them back to the old orings and long grey spring, now there is no leak....wtf just happend ? lol

possibly...is the gold spring new or used? if it's used, does it extend past the bolt or is it flush with the tip? a worn out spring could cause a leak down the barrel as it wouldn't push the bolt back all the way. as for changing the o-ring and the leak being worse...some new o-rings are bad, if you can believe that. the tolerances are not that great for o-rings, which is why there are many different sized o-ring carriers for the lvl 10 bolt.

*edit*
speaking of which, if this is for a valve with a lvl 10 bolt, and it's leaking down the barrel, first try cleaning and oiling the o-ring. if that doesn't help, move to the next smaller carrier (be sure to use the same o-ring). there is a large thread dedicated to lvl 10 issues; there's a mountain of info there and several sharp people who will be glad to help.

[Tunaman]

DONT use the long grey spring! You will never get it working right. Start with the small gold spring.

[athomas]

Just moving the valve around probably fixed your leak problem. If the edge of the oring is that close to the bolt stem vent hole, then it will probably come back.

When you slightly pull the trigger, you are pushing the bolt back a tiny bit, which also pushes the bolt stem vent hole farther past the sealing edge of the oring. That tells us that hole is too close to the oring. Remove the powertube shims from your level 10 setup if they are installed. That will allow the carrier to move farther forward and get the sealing edge of the oring away from the bolt stem vent hole. If you don't have shims installed, you might want to inspect your sear for wear at the tip where it holds the bolt.

[astr0xz0mbie]

well got air in the tank and switched from the gold spring to the red spring and the leak stopped so i degassed it and put the gold spring back on and the leak started up again so pretty sure cyco hit the nail on the head with the gold spring not resetting the bolt back all the way. only leaks with the gold spring. grey and red springs do not cause the leak so im just going to stick with the red

[athomas]

only leaks with the gold spring. grey and red springs do not cause the leak so im just going to stick with the red

That'll work when dry firing because the air chamber empties each time. The red spring has more force pushing back on the bolt and seats the bolt stem farther past the oring seam. That won't happen every time, especially once you start firing balls and there is residual pressure left in the chamber pushing back. If the reset action needs more force to hit the bolt stem farther into the carrier, then the carrier is sitting too far forward during normal operation. No matter what spring you use, the bolt always sits forward against the sear when everything is at rest. That relationship never changes. If it leaks at rest, then a different spring won't change the location of neither the bolt nor the sear. So, you need to fix the real problem if you want it to consistently seal and not leak down the barrel while at rest.

[Cyco-Dude]

That'll work when dry firing because the air chamber empties each time. The red spring has more force pushing back on the bolt and seats the bolt stem farther past the oring seam. That won't happen every time, especially once you start firing balls and there is residual pressure left in the chamber pushing back. If the reset action needs more force to hit the bolt stem farther into the carrier, then the carrier is sitting too far forward during normal operation. No matter what spring you use, the bolt always sits forward against the sear when everything is at rest. That relationship never changes. If it leaks at rest, then a different spring won't change the location of neither the bolt nor the sear. So, you need to fix the real problem if you want it to consistently seal and not leak down the barrel while at rest.

so this problem would imply the bolt and / or sear are worn out?

[Laku]

Or that there are shims in the power tube.

[athomas]

so this problem would imply the bolt and / or sear are worn out?

The presence of shims is the obvious culprit in most instances. If there are no shims installed, then check the sear. Its not usually the bolt, so I wouldn't worry about that. It could be your rail bushing. Sometimes, its just a combination of tolerances in the wrong direction that add up to a value that don't allow the correct spacing for the bolt in the powertube. That one is rare, but can happen. If all parts are in good condition and in place, then you can still make it work by shaving a tiny bit off the back end of your powertube tip.

[zulubravo44]

what about the opposite problem on a freshly set up pump mag (AM valve, level 7 bolt).

it seals fine in both the cocked and uncocked position. however, when i depress the trigger slightly, i can actually get the entire dump chamber to empty before the bolt actually fires if pulled slowly enough. if i pull the trigger quickly (jerking instead of squeezing, bad habits to get into), it seems to fire just fine.

i shortened the bolt spring so it is flush with the end of the bolt now and it seems to have improved slightly. any other ideas? it doesn't seem like it would be power tub o-ring, since it's the inverse symptom.

[athomas]

what about the opposite problem on a freshly set up pump mag (AM valve, level 7 bolt).

it seals fine in both the cocked and uncocked position. however, when i depress the trigger slightly, i can actually get the entire dump chamber to empty before the bolt actually fires if pulled slowly enough. if i pull the trigger quickly (jerking instead of squeezing, bad habits to get into), it seems to fire just fine.

i shortened the bolt spring so it is flush with the end of the bolt now and it seems to have improved slightly. any other ideas? it doesn't seem like it would be power tub o-ring, since it's the inverse symptom.

The problem could still be a worn sear or possibly a worn bolt. If it is badly worn such that the tip no longer has the proper angle, then it could let the bolt creep forward as you pull the trigger. It would have to be worn pretty bad for this to happen. I would change the powertube oring first and then use a shorter powertube spacer than you are using now. The shorter powertube spacer will compensate for any forward movement and maintain the seal at the back of the bolt stem.