For those that have not looked under the differential of an early Chevy / GMC truck, the following may be of interest.
Protection of the metal rear brake lines are shown in the attached photos from a 1939 Chevrolet ½ ton. They are separated by a brass division block (gray in photos) which is on the right side of the differential.
The result is a much shorter brake line section on the right side that connects to the wheel cylinder. It is interesting to see how GM protected the lines from stumps and rocks in the field. The line reaches from the top of the axle housing down to the wheel cylinder it is run behind and above the shock attachment arm and spring attaching bracket. It is kept away from incoming materials as the truck is driven in very rough terrain.