Grand Caravan feels with breaks on in slow traffic

take it to any brake/repair shop and get an idea...

probably a caliper sticking. You can jack the car up, remove the caliper and try compressing the piston with a c-clamp. If it is a rear caliper that is sticking, you may need to apply pressure and rotate the piston at the same time to compress it. A c-clamp and channel locks will work for this, but its difficult and you can easily tear the rubber boot around the piston. They make a took you can usually rent from Advance or Autozone to do that. Search google and I'm sure you'll find plenty more info. Calipers are a little pricey and there is a core charge involved but it's never been worth trying to rebuild one to me. I've had calipers freeze up on 2 different vehicles.