Originally Posted by helitom
......It has happened when going downhill pulling my 5th wheel R/V, and has happen with just my ATV in the bed (appx 600 lb)......
Check your trailer brakes on the 5th wheel trailer. If the brakes are not working properly most of the stopping is done by your front brakes, which will overheat them. The subsequent brake jobs just make the rotor thinner and more prone to warping.
Also the chattering is probably caused by a failure of the brake techncian to properly clean and lubricate the caliper slide pins. Common problem on SD brakes.
(Yes, even Ford techncians screw this one up on a regular basis)