Volvo Driver seatbelt temporary fix with dental floss, and final replacement - YouTube
On Saturday, the driver's seatbelt on our 1996 Volvo 850 would not extend and would only retract, i.e. get tighter. After a nerve-wracking drive home without a seatbelt, I took it apart and rigged a temporary fix with dental floss to get us through the weekend.
AS FAR AS I CAN TELL, THE TEMPORARY FIX DID NOT INHIBIT SAFE AND PROPER RESTRAINT OPERATION OF THE SEATBELT, BUT I CANNOT SUBSTANTIATE, AND DO NOT GUARANTEE, ANY SUCH CLAIM. IT JUST GOT US THROUGH THE WEEKEND.
The dental floss made manual the ability to extend or release the belt under normal driving conditions, which operation is normally automatic. It was annoying because as you drove, the belt would only get tighter and would not release without a gentle pull on the floss, which was needed to look around at intersections, while backing, and such. A piece of soft foam between the belt and collar bone would have been a welcome improvement.
On Monday I got a used replacement from Ithaca Foreign Car Service (Thanks, Dave et al.!) and replaced the bad unit.
This video shows the replacement, the inertial device which seemed okay but was apparently no longer doing its job, then some details of the temporary fix with the floss.
I did forget to video the feeding of the seatbelt through the side door post plastic panel. Also, posts in some fora state that a SRS error will be generated if the battery is not disconnected during this operation.