The calipers are the parts on your Ford F-150 that do the physical act of braking. By clamping the brake pads down on the rotors, they slow the car down to a stop. That clamping action is done with a hydraulic cylinder, and over time it can leak, lose pressure or stick, causing all sorts of braking issues. That's when you must pull the calipers off and replace them with new or reconditioned ones.
Lift up the front of the F-150, using the jack, and secure the truck on jack stands. Make sure the truck is completely secure on the jack stands before you crawl underneath it. Remove the front wheels using the tire iron, and place them to the side, out of the workspace.
Place the brake line clamps onto the brake line leading into the caliper, and clamp them down onto the line until the line is collapsed. Disconnect the banjo bolt that leads into the caliper, using a 3/8-inch ratchet and socket. A little brake fluid will leak out onto the ground, so make sure it doesn't touch your skin or painted surfaces if possible.
Unbolt the brake caliper from the spindle, using the 3/8-inch ratchet and socket. There are two sets of bolts on the caliper; depending on your needs, you can remove either one. The bolts on the spindle are the entire caliper, including the bracket, which you would want to remove if you were changing the entire braking system. If you're just getting new calipers or want to get yours rebuilt, you can disconnect them at the bracket, which is between the end of the caliper and the spindle.
