I have a problem with the rear brakes getting real hot. You can smell them after several stops or when pulling my lawn trailer. Keep in mind thet this problem recently developed and I have not increased the trailer weight or changed tire size on the truck. I have replaced the front rotors and pads, new master cylinder, new rear wheel cylinders ,drums and shoes. Yes I have bled them several times. I took a temperature gun and measured the temps of the front rotors compared to the rear drums after several stops with my trailer. The fronts were about 160 and the rears were about 350. I know the fronts should be doing most of the work so what can it be??

 

Either the e-brake is hanging or the brake fluid cannot exit the rear wheel cylinders when the brake pedal is released. Rubber brake lines often cause this effect when they swell shut or are crimped by a bracket that rusts and pinches the line. There's plenty of hydraulic pressure to activate the brakes, but the pressure can't release since the hose is acting like a checkvalve.

If you had comparitively low fluid flow at the rear cylinders when bleeding, I'd suspect the hoses.

Both sides or only one?

Steve

 

both sides.

 

Maybe an over simple question but did you replace all the hardware with fresh pieces? All the springs.
If the springs were not replaced they may not be strong enough to reteract the shoes and cause them to drag and heat up....

the more they heat up the weaker the springs become--> the weaker they are the more the shoes drag and heat up.... a viscious cycle!