Anti Lock Brake Problem

I have a 99 Dodge Dakota that is mysteriously engaging the front brakes while travelling down the road. This happened first when Son #2 borrowed the truck, but since I wasn't in the vehicle (and he breaks things...a lot) I just assumed he had abused something. After the first episode, I replaced all the brakes, the master cylinder, and the calipers. It worked fine for a few weeks, but the same problem happened to me yesterday. It just started engaging the brakes and lugging the truck down. My guess is that something is wrong with the anti lock brakes, but that is just a guess. If any of you are aware of how I could confirm this, one way or the other, I'd appreciate the pointers. Also, if it is the anti-lock brakes, can they be easily disengaged or would this affect the rest of the braking system?