On my 93 lumina Z34 my seat belt straps don't lock in place. What I'm talking about is after I buckle up the slack from the strap rewinds itself into the door and should lock in place but I can pull the strap out. Both front driver side and passenger side does this. The seat belts are useless if the straps don't lock in place. Anyone out know why the straps don't lock in?

They are inertia reel type, it takes a sharp jerk to get them to lock, otherwise they are free to reel out.

If a sharp quick tug doesn't make the reel lock momentarily, take the cover off the reel and clean the mechanism. Sometimes they get dirt, dust, dog hair or whatever in the mechanicals and the centrifigul part won't move fast enough to make them lock up when needed.