One problem related to seat belt has been reported for the 1997 Volvo 850. The most recently reported issues are listed below.
Integrated booster seat broke apart at hinge linking seat to seat-back (seat belt functioned, but only to hold the integrated booster seat in place). The metal hinge broke into 4 pieces and completely disengaged from the seat/back. The seat was used by only one child, and at 55 lbs well below the weight limit of 80 pounds. The integrated booster seat remained in the booster-seat position most of the time and was not subject to an unusual amount of opening and closing. This suggests a serious design flaw that could jeopardize the safety and even the life of a child strapped into the integrated booster seat. If the structural integrity failure was not noticed by a parent and the vehicle was involved in a high-impact crash, the seat could disengage from the vehicle itself, propelling the child into seats or windows.