Rear Brake parts

[Gez89SHO]

Hey guys, I'm trying to get my parking brake working and I've narrowed it down to the rear caliper. This is the rear driver's side. The caliper is new, just replaced. The cable was replaced in the fall, and it is fine. The return spring loosens the cable,but not all the way.

I'm thinking it may be the brake return spring. I searched for the individual part and rockauto lists two parts:
Wagner Part # F113368 Return spring kit
Wagner Part # H315 Return spring kit

Does anyone know if this is the correct part? No pics are provided so I'm not sure.

 

[dstig1]

That doesn't quite make sense. When the e-brake is released, the spring pulls on the cable to lift the e-brake pedal, so I don't see how you are describing it as "loosening the cable partway." If the return spring lever on both calipers goes to the fully released position but the pedal doesn't, then the problem is in the cables, most likely.