So today I have tried to create exploded view lines to reference points and axis' for the first time. And guess what? It won't let me pick them. Here I am attempting to point the line to the center of the slot and i have to select one end or the other. I can drag the line around a little and fake it, but shouldn't we be able to pick the axis at least?
Then I would model just a cut rough profile section of the universal bumper and change the transparency to like 75% - then when you explode the assembly, the bumper profile would show and you could run your line through a hole in the bumper if you need to make a 90 turn etc..