Door Hinge problems of the 1996 GMC Savana

This is a commercial vehicle used in transporting interior decorating items. On or about 8/2/04, I delivered a table top to a client and upon opening the rear side doors (both doors) the upper hinge on the furthermost rear door broke. I had noticed a rattling sound prior to this date, however I thought it was items inside the vehicle. The door is only being held on by the lower hinge and the other door closed upon it. I am fearful that the other hinge will suffer a stress fracture and possibly the door will fall off. I researched through this site and found two incidents of service bulletins (September 24, 2001 and June 1,2003) notifying that customers have complained that the door hinge binds. This had occurred to me also, prior to its breaking.