2005 F250 SD rear brake problem
 

My 05 f250 sd 4x4 developed a problem with the rear brakes. When almost stopped the rear brakes seem to pulse .I first thought it was a bad rotor but after removing rotor it does not appear warped. I have seen rotors in much worse condition and they did not exhibit this problem. It almost seems like the abs is activation on the rear rotors. Anyone see a similar problem?