Our C4 UrS-cars have an independent suspension that involves an unsprung fixed rear differential feeding power out to the rear wheels via CV-jointed half-shafts. These half-shafts go through bearings that are mounted in wheel bearing housings. These bearing housings are attached to a lower control arm (trailing arm), a coil-over shock and a track-control arm. The various bushings involved can all wear, leading to rear wheel directional sloppyness, causing you to think something is wrong with the front steering (in fact the rear is randomly trying to steer the car).

Lower (showing the rear diff and the trailing arms)


Rear Axel and Bearing info:



Rear bearing housing:


Upper (showing track control arm)