A couple of weeks ago I did the rear axle brakes on my '05 ram 2500 single axle. I replaced the left caliper and turned the rotor. I replaced the right rotor, but kept the caliper (it looked newer and all the rubber was in tact) I bled the brakes, all 4 wheels. Today I smelled the brakes burning on the right rear, what would cause this to happen? I can't see yet if there is air in the line (wifes not home!) I need this fixed tonight, the truck works tomorrow. Should I just get a new caliper, although it looks newer it does have chrysler logos on it.

 

When you replaced everything, did you use high temp grease on the slides and bolts? it sounds like a slide (or guide) is sticking. Another thing that could cause this is a sticking piston.

 

A brake hose with a collapsed inner lining can also cause the same problem.
The loose lining can form a flap inside the hose acting like a one way valve not letting the pressure release. More likely to happen when the hose is moved around when work is being performed.