Just in front of the rear tire front leaf spring connection the rear brake cable passes through a round metal loop. pull on the cable to move the cable a little bit through the loop and check the cable, it WILL be worn down to the metal. this is what makes the noise. some electrical tape around the cable kept the metal from coming in contact and fixed the problem.

I have a 2007 ford focus, squeak coming from rear of car, almost sounds like inside, I have determined that it is coming from the Rear trailing arm front bushing.