Remove the barrel, add oil in the asa, cock the marker then air it up. Shoot it a few times listen for a leak. If it leaks there's a bad seal.
No leak, remember the cock it before airing up.
SO... u saying just o-ring broken? I took it apart and checked them, and they seems fine to me, no cuts, no broken at all
I worried about the most is those expensive parts like bolt, hammer broken, then I have to buy the new one.
What is the purpose of cock the gun b4 airing up? I never do that, I always airing up my gun first, then cock it. Is it bad for the gun?