How to fix a fill valve

[Stuey]

I have a problem with one of MP7 magazines - the fill valve doesn't seem to work properly. It fills as normal for about the first second but then it starts spewing liquid gas straight back out, despite being a silent fill valve. Thus I can't fill the mag properly. Short of just buying a new valve, what do I do?

 

I know you can take these things apart, but I can't figure out how.

 

Here is the valve:

 

[Tom Andrews]

The little brass collar at the bottom should unscrew, revealing a spring and a collared pin with a tiny O ring. Problem is removing the brass part without marking/distorting it.

 

Sometimes they just unscrew with finger pressure, sometimes you need gentle force withpliers. Try not to use those with serrated jaws.

 

After all that, I have no idea what is causing your problem re filling.

[Stuey]

Well I just took it apart (needed a vice and pliers) and put it back together and it works! No idea what was wrong with it, but as far as I'm concerned Mr. Andrews you just fixed my gun - thanks!

 

https://www.youtube.com/watch?v=v3rhQc666Sg

[Inari]

Most of the time it's as simple as something being out of place slightly, and reseating it solves the problem

[renegadecow]

But sometimes it's not and you have a torn o-ring. The little one especially is hard to find replacements for; good thing there are disposable lighters.

[Stuey]

Speaking of which, does anyone know the dimensions for the silent fill o-ring? If I knew the size I'm sure I could get them cheaper than here.

 

I've just taken apart one of those Chinese grenade gas charger things, I think it needs a new o-ring inside the fill nozzle on top, tiny little bugger...