Brake line from the master cylinder to distribution manifold has a pin hole leak. Looks like the line has had a previous repair. Line as had a braided portion installed just above the leak. Is there a stainless steel replacement line available? What is the purpose of all bends towards the bottom of the line before it goes into the manifold, are the fittings at each end of the line the same?
The bends in the lines are to absorb vibration. The braided sections are because the body wobbles on the frame and the repeated bending caused the metal to work harden and crack. You can try getting a replacement line from the dealer but they don't do a good job of supporting vehicles more than about five years old. Auto parts stores are doing a pretty good job of supplying parts Ford doesn't want to. If they can't help, you can make a line by starting with a pre-manufactured steel line about two feet long, and use a tubing bender to make three loops about three inches in diameter. It will look like a giant spring when you're done.
You'll need to remove the old line first to see what ends they used. Ford used a line on the rear of the Taurus with a double flare on one end and an iso flare on the other. Double flares are easier to make so if you have to make a line with loops in it buy a line with two iso flares, cut one off and make the double flare for that end. The aftermarket parts suppliers are making the lines for the Taurus so there's a good chance they're making parts for your truck too.
If you do this right you won't have to bleed the system down at the wheels. Leave the lower fitting loose, then pump the brake pedal a few inches, (never more than half way to the floor), to run some brake fluid down the new line. Once no more air comes out tighten the fitting, then push the pedal again slowly, then let it release quickly. Any air bubbles will float back up, then they'll wash into the reservoir with the brake fluid that's rushing back.