Im not sure how the braking system is on a 38...
These tube nuts only go between two wheel cylinders on each side of the truck, only on later models. Typically the brake lines connect to a brass block that has a hole through it where a banjo bolt (hollow bolt) slides through and connects to the wheel cylinder. There are also copper washers that are on either side of the brass block and give a crush seal to the banjo bolt and wheel cylinder.
Does that sound right???
Jeff
