If I understand your post, you are able to move the external release lever through its full range of motion with little or no resistance, is that correct? You may have a broken pivot, or the pneumatic coupling device is not connecting the external lever to the internal linkage. An endoscope will be helpful here.

This link will show you how to engage the coupling that's operated by the pneumatic device.Insert the screwdriver as shown by the red arrow. Good luck! https://www.crossfireforum.org/forum...all-locked.pdf