Now, behind the frame rail where the notching needs to happen is a wire harness and your power steering return line. Some people claim that they had to disconnected the wiring harness that runs to the drive side of the Jeep and ends at the ABS sensor, pull it out, and reroute it above the cross member to ensure it's out of the way. I did not have to do that.. I simply pulled some tabs loose and used a bungee cord to hold the harness out of my way during cutting and when I was all done It tucked up nicely in the corner with a few zip ties holding it in place.
The power steering return line is impossible to reroute without cutting it apart. It's a formed hard line with a small section of rubber but the hard line is formed around the cross member. Only option I saw was cutting the rubber line up top and using a 3/8 barbed fitting to splice a new rubber line onto it, then cutting the hard line past and below the cross member and running a new rubber line to that with a couple hose clamps. All said and done it came out great and only took me a couple hours.
Below you can see where I clamped the line so not to drip anymore fluid than I had to. You can also see the tube that I used to layout my notch and use as a filler once it was all cut.
Untitled by Daniel Avis, on Flickr
Welding in the modified tube to add strength back into the frame.
Untitled by Daniel Avis, on Flickr
All said and done with some paint on it.
Untitled by Daniel Avis, on Flickr