well saab owes you a new one there is a recall on all of your seat belt retractors. I did a little extra checking and found thids recall for you. that spring is probably broke in there.
DEFECT: Some of these passenger vehicles were built with seat belt retractors for the front seats that were damaged during the manufacturing process. If damaged, over time, the Automatic Tensioning System (ATS) cable in the seat belt retractor could break, causing the belt webbing to not retract. In the event of a crash, a front seat occupant may receive more severe injuries.
REMEDY: Dealers will replace the seat belt retractor assemblies. The manufacturer has not yet provided an owner notification schedule for this campaign. Owners may contact Saab at 1-800-955-9007.