I own a hydraulic shop. What O-rings are you using? The fitting in the pic is O-Ring Boss thread, the port it threads into will have a recess for the o-ring. If that is what you are using it takes an SAE O-ring Boss BUNA O-ring, just any old o-ring will not work and will fail. Any hydraulic shop will have o-ring kits for ORB fittings (they come in standard sizes) and many will just give you an o-ring or two, at least that is what we do in our shop.
