ok so i just replace my rear pads and rotors (during part of my tune up job).

Go to move the car today and hear a lot of hard sqeaking .. i looked at the rotors and they have black streaks on them .. in a perfect circular pattern. This leads me to believe that the calipers are stuck open?

If that's the case what could be the cause? bad brake line .. bad calipers?

It's on both rear wheels.

2006 tribute v6 4wd model with disc brakes in rear

 

All mine have drum brakes so I’m not familiar with the disc setup but in general a couple of things come to mind:

if the pads are making noise then a caliper piston may be sticking, did you fully retract them when you changed the pads?

Did you relax the handbrake mechanism? Some require the piston to be rotated as it is retracted if the handbrake act on the main brake pads, other setups have dedicated handbrake shoes.

As you changed the rotors they could be thicker than normal (never heard of it but in theory...)

 

I figured it out the noise was the parking brake hies stick open . There were 2 issues.

First the parking shoe actuator was seized from rust.

second the brake shoe retaining pins were floating bc the backing plate rotted out.

i fixed the actuators by filing off the rust. And then i fixed the retaining pins by using screws and washers.

It all works nice now!