Finally, install the air line, making sure it doesn't touch any parts, especially the ring gear and the carrier. Work carefully not to crimp the line. Attach the two provided ferrules. The one with the flat end fits on the outside of the tube. Test the pressure in the line. Our prototype needed an elbow to fit outside the carrier that would connect it to the air lines, so the guys at Tri-County fabbed one up. (ARB will include all necessary parts when this locker goes into production.) Once preload and backlash are adjusted to their proper settings, return the axletube to the diff and reattach all the frontend parts.