[Mampoer]

I needed to do this to remove broken barrel and replace with new one. Instructions were brilliant and everything went well. I now have the new barrel but cannot refit it. The problem is that when I depress the 'bridge' half way down the barrel it keeps popping back up. Any suggestions? Am I simply not pushing it far enough down? I can get it to lock in the closed position simply by turning the steering wheel to locked position. But there doesn't seem to be an equivalent way of locking it in open position. Can anyone help?