I drive a dodge van 3500 ram 15 passenger van. While driving at highway speed, my brakes come on. I pull over for 5 minutes and let it cool. I drive away and it doesn't do it again. I've replaced the brake pads and the rotors and bled the brakes and the problem continues. Does anyone know how to fix this? Also, it only happens when it's hot outside.

 

As you mentioned outside temperature is warm when this occurs, you may have contaminated brake fluid. If I recall properly others who had similar issues replaced all the rubber brakelines which swell and cause the brakes to drag. I believe purging all present fluid should be your first step as contaminated fluid was a lower boiling point.

 

What do you mean by "come on"? Is it like someone is pressing and holding the pedal, is it the brake light on the dash that comes on, does it happen while driving or only after you've applied the brakes and they fail to release?