While every part of the axle is almost equally important in propelling the truck forward there is one part of the rear axle, not related to forward movement, that is more important that then entire assembly. The brakes.
As with any custom housing custom brake lines are going to be needed. In my case I am converting the axle from Drum to Disk brakes so I needed all new hard lines, and new soft lines to connect to the calipers. Along with those standard lines I also need a new soft line to run up onto the upper suspension link, hard line on the link, and more soft line to get from the link to the frame. Did I lose you yet?
I took a trip down to my local hose supply company and explained to the guy behind the counter what I was doing. He knew exactly what I needed and set me up with four lengths' of braided stainless steel soft line, two for the calipers and two for the upper link, custom made to the lengths that I had told him. He also set me up with all of the fittings and two lengths of 3/16 stainless steel brake hard-line. I then headed home where the cutting bending and flaring would commence.
I chose to route my hard-line around where the frame/air bump can/will be hitting the axle housing in a effort to protect the lines should the bumpstop fail. They then route up to a junction block on the back of the crown and from there a section of braided stainless soft line takes makes the transition onto the upper link. This piece, along with the line at the frame side of the link, had to be soft so they can move and flex with the movement of the suspension.
The lines are held to the axle with stainless steel (notice the trend yet?) button head bolts and stainless clamps on the hard line and are held at the ends by a rubber grommet. The way the ends are held on are entirely personal preference. You can use the style I did and a grommet, or a bulk head fitting, a c-clip, e-clip, or any variety of other ways.
The brake lines were removed after being assembled so the housing could be painted and readied for final assembly.
By now you may be wondering how this can be a 'budget' build with all of these stainless steel parts. I'll level with you, at this point I have veered slightly away from budget, but the principles still exist. You could easily plumb your housing in the exact same way as I using rubber hoses and steel lines. So you see, it could still be done budget mindedly!