Unusual brake issue

[TerriJo]

I have an unusual problem with the brakes on my 2002 jeep Grand Cherokee laredo. The rig will suddenly feel like it's being dragged backwards. This usually happens on warmer days and after it's gone 25 miles or more. When this happens, I can't drive over 35mph due to the violent wobble it develops. When I use the brakes under this condition it REALLY gets to shaking. My boyfriend says this one has him stumped and he's pretty good with cars. The rear brakes are hot when this happens. How do I get it fixed? Help!!!!

 

[mark sr]

A faulty speed sensor can engage the brake but that normally just affects one wheel - which will get hot. But that won't cause a wobble as far as I know.