You need to lubricate the caliper pins with silicone grease or Squeak Relief, which is silicone grease with moly. An excellent product to use in this situation is Motorcraft Silicone Brake Caliper Grease and Dielectric Compound (XG-3-A). It's available at your local Ford or Lincoln/Mercury dealer. If the caliper pins are worn, they can be easily replaced.
This link should help:
http://www.askmehelpdesk.com/cars-tr...ml#post1618425
You want to also completely change the brake fluid every 2 years, which is particularly easy to do on trucks. I'd recommend Valvoline Brake Fluid for your truck.