I just had a front disc brake caliper bolt come loose on my '02 Ranger. Fortunately I was poking around a parking lot at the time as the loose caliper would lock up that front wheel - but only while driving forwards. I had just rebuilt the front end of this truck three years ago and was careful to fully torque all the bolts. I did not know that those caliper bolts must be coated with the blue Loctite! Luckily I was not running down the interstate when this happened. I have since read about others having had this problem.