Notice also that inertia weight rust up to lock the roller, but I guess is you hit something hard enough, haven't tried it yet, may work free. All started with shoulder belts, if that weight doesn't move forward, the lap part of the belt can also become loose. An old fashion type lap belt never would come loose, so for all practical purposes, shoulder belts are worthless. They know this, added air bags like crazy. If these things don't kill you, not good at all for short people, one size does not fit all.Had the same problem with our '92 Saturn SC. The shafts the belt reels turned on had rusted/corroded and bound up the mechanism. I was able to take them apart, sand the corrosion off, and coat the shafts with low temp white lithium grease. After 20 years the retractors still worked fine for my Brother-In-Law.