What could be the reason for line 2 to come out? The O ring inside the line is damaged and I had to replace the whole line. Can be something plugged somewhere? What should I check before I put the new oil lines in?

Also, what is the torque for the these lines (number 4 in the pic and for line number 2). I tried to look it up on TIS spaghetticoder and I couldn't find it.

http://realoem.com/bmw/diagrams/n/d/106.png

thanks