acm m500 always leaking gas!
 

its leaking gas into the main canon i check o-rings every thing seems fine but its leaking any idea!?

They leak a lot.

From what you described though, it sounds like the valve stem isn't seating properly on the o-ring; UNSCREW the main valve (the one at the rear of the gas block) a little bit -- yes it sounds wrong, but if you look at how it's built you'll understand why its leaking if its screwed in too much.

I just repaired my ACM m500 while it was on the bench waiting for an HPA conversion. Actually, it was in a box in pieces for months. It now holds gas for weeks instead of only an hour or so.

I won't have time to write something up just yet but when I swap my full valve for an HPA adapter, I'll take pics and post it up.

Mine leaked too.
I stripped all o-rings and let them soak overnight in 10wt silicone oil when I installed steel cocking levers.

Let me empty all 3 tubes with a single charge until I sold the thing.

Basically, soaking mine in silicone didn't help much. Always had a slow leak. Replaced orings and teflon taped the heck out of all the fittings. Nadda. So I let it sit in a box for months until one day the itch to go HPA hit me and I was directed to the adapter. (thanks aZn_triXta07)

Once I ordered the parts, a full break down of the gas block was in order. When removing the valve, remember to remove the very last oring behind the brass spring cup. I gave it a good soak for piece of mind and the reinstalled everything. There was still a slow leak as usual so I said screw it and blue gasket maker sealed the valve and the plug just below it. Worked like a charm.

It now holds a full charge and can empty all loaded BB's in all 3 tubes in without a recharge. I also modded the loading mechanism to load and shoot 5 BB's instead of 3 at a time.

I might be in the market for an 8mm version now. :)


edit:
lol! really? http://www.airsoftcanada.com/showthr...52#post1640252
it's such an easy fix!

I have a Marushin M500 6mm that would hold gas and it was shooting up until last week when I lent it out to a teammate and about 15 minutes into the game it started releasing gas at a pretty good rate from the barrel.

So long story short Coach if you could post a tutorial whenever you can I would be interested in that even if the OP just wants to dump his gun.

Thanks in advance!

Yeah, but they are in stock at some retailers for less than that...
Depending on what type of oil and what additives is in there, it might not work. Break cleaner for 10 seconds also works good in expanding o-rings... just don't forget them in overnight, they won't be there.

less than what? oh the link to OP's sale thread? yeah, I'm not interested in another 6mm version.

what might not work? my ACM m500 is rock solid!

I used 100% silicone oil and let the orings get a good soak. I'm not really sure I follow your post.