I never thought I'd have this simple, basic issue but here I am.

I'm replacing a steel hydraulic line on a John Deere 4110 tractor, the link below is an exploded diagram of the area. In the picture I'm trying to thread the bolt (#4) through the metal line and into the machine. https://imgur.com/a/pWYqwJ9

The bolt came out fine, threads have been triple checked and no damage found, it threads perfectly by hand without running it through the hydraulic line. My conclusion is that the metal line is slightly tilting the bolt, stopping it from threading. I wiggled the line up and down while trying to thread the bolt for over an hour, no luck. Angled the bolt every which way I could but it's apparently not enough and because it's a steel line I can't move it around much.

I'm utterly out of ideas, ready to call someone else and doing this as a favor for a dear family member. I don't want to fail so I'm going back in the morning to try again and if needed I can take pictures.