I agree with the above, it sound like a missing caliper pin. The metal in the steering knuckle apparently is pretty soft and it is easy to misalign the pin in the rubber sleeve. My self and a number of others have done it. Pull the wheel and inspect the caliper. Check the threads. If they are stripped, Auto parts stores have oversize self tapping caliper pins. (I have two in one side) Or you can get heli coils.
99 Durango 5.9, FT 4x4, IP stage III w/ K&N air hat, M1, SCT, Fastman TB, 1.7 RR, JBA headers, Borla cat back, Martin Saine valve body, Hotchkis swaybars, Blistein shocks, lowered 2" Black Rhino Kenya wheels, 246. 7 RWHP, 319 TQ