Again, I would say its probably that axle and it has most likely taken out the bearing by now. I would start there with replacing the axle and bearing.
Groaning brakes can be a number of things including glazed pads (from overheating), improperly broken in brakes, uneven mating surfaces (grooved rotors or pads), and glazed/overheated/heatchecked rotors. Noise in brakes is almost always caused by a vibration. Usually the higher pitched the groan or squeal the faster the vibration. For example if your pads are slipping and grabbing they can groan because of the "vibration" from slipping and grabbing.
2009 Ford Focus Sedan SE--Amber Gold Metallic--FS Cool-flo intake, 17" Black Kazera Rims with Potenza S-04PP, Custom 2.5" Exhaust.