Automag leaking down the barrel.

[Eddie9195]

Ok yesterday I picked up a used Automag. I attached the air tank and it leaks down the barrel and stops when I hold the trigger. I have read a couple posts about similar leaks and one said the o-ring the the powertube needs to be replaced or lubed. Where is this o-ring? Another post mentioned the on/off. What exactly would the problem with that be, and how do I fix it?

I went to the AGD website and printed off the manuals and diagrams, so I think I am on the right path. Also where can I get parts?

This is the first Automag I have ever had so I am not very familiar with it at all.

Thanks for the help.

Here is a pic of what I got. I got it for $60. Did I get a good deal?

[SchoolU101]

I assume that you are using a classic valve (there are different valves, check to see which one you have).

Spare parts (including replacement o-ring packages) can be purchased from the airgun.com online store.

First things first. Put 5 drops of oil in the ASA, gas up and shoot it through the valve.

To replace the powertube o-ring (most likely to be the problem):

De-gas the marker. Unscrew the thumbscrew located below the back of the valve. Pull the trigger and slide the valve out. Remove the bolt. Unscrew the powertube-tip with a nickel. Pull out everything inside the powertube. There should only be one o-ring in there. Replace/oil it.

If that does not fix it...

The on/off assembly is located on the underside of the valve. Pull it out and look inside the hole. There should be 2 o-rings at the top, a urethane o-ring and a Teflon o-ring (one inside the other). Take them out, replace and oil.

[michbich]

If it doesn't leak when you hold the trigger down, your on-off is fine.

If it leaks without touching the trigger, the problem is with your powertube. I would start by checking the power tube oring. Chances are, it's your powertube oring, but it could also be the powertube spacer (it might be missing) showed in the second pic.

Like i posted in a different thread:

This is the o-ring you might want to concider replacing or oiling.


The o-ring on the brass power tube tip is to prevent from unscrewing. It doesn't actualy seal anything.

[Eddie9195]

Yours is one of the pics I had seen before.

I know the powertube spacer is there, so my next step is to check/replace the o-ring then. Do you know the size?

Thanks for the help. I will look into it after work today.

[halB]

Same size as the o rings in the on/off. One of the o rings in the on/off is NOT a sealing o ring, and can be swapped with a bad powertube o ring. That's the genius of AGD To find out which one is not a sealing o ring, please contact your manual.

[Eddie9195]

OK I checked the powertube o-ring last night. It looked in good repair. I pulled it out and cleaned and lubed it up and put it back in and it still leaked. Not good. I think I will just buy a rebuild kit if one is available and replace all the o-rings just in case.

Thanks again for the help.

[BiNumber3]

your bolt spring may be weakened if the mag is old, so the air pressure is pushing the bolt past the powertube o-ring just enough to allow for leakage, or your power tube spacer may be too long.

[Eddie9195]

I think it is an older Mag. I will look into getting a new spring and a spacer kit.

I also adjusted the rear regulator and was able to get it to stop leaking by turning it down. It would not fire though. Any ideas?

Thanks again!

[classic68]

Even though the o-ring looks good it can be hard from old age. It will not seal properly. You can buy a rebuild kit which will have all the o-rings you need and a new bolt spring. I just bought an old 68 classic (had one years ago and loved it) and had to replace all the o-rings because of age. If you live near by I would be happy to show you how to replace everything. I live in South Carolina.

RJ

[Eddie9195]

Thanks for the offer, but I live in Oregon!

Thanks also for the advice. I will look into getting a rebuild kit for it. Hopefully that will cure it's ailments! I have always wanted a Mag and for some reason never bought one until now.

[michbich]

If you have some non-petroleum grease, I would grease the powertube oring and air it up. I had a leaky oring that wouldn't go away by oiling, but since the moment i greased it, i have not heard from it since then.

[Eddie9195]

Thanks, I will try that.

[Hazardous/2k4]

michbich help me out i pm'd you

[Wanta B Sniper]

I am having a problem similar to Eddie's. I have a 68 Classic valve, when I air it up sometimes I can fire one or two shots and then it will leak down the barrel. If I hold the trigger the leak stops but still lets out tiny bursts of air (two or three seconds apart) with the trigger fully compressed. I put oil in the ASA and aired it up and the power tube o-rings had some lube on them. The o-ring on the brass tip of the power tube had a tiny strip peel off but I think that I have read that it is only there to hold the tip in place.

My first guess is that the problem is the spring, any other guesses?

Thanks!

[211]

WBSniper-
the tiny bursts while you are holding the trigger means bad on/off top oring (the small white one in the center of the larger one)
the slow leak sounds like power tube spacer issues
the powertube spring is an old design, get a new brass spacer kit, then fit the spacers until you find the one that fixes the leak