Upon attempting to back up from a parked position, an audible "pop" was heard by the vehicle operator and three bystanders. The vehicle then stopped motion after about five feet of travel as the right rear wheel was locked up. Upon visual on-the-spot inspection by company mechanic, it was obvious the casting attached to the axle end which acts as the support for both the brake caliper and the parking brake had "exploded" with a large piece shooting onto the ground and other pieces jamming up in the drum part of the rotor assembly causing the lock-up. Vehicle immovable, was flatbeded to the selling dealer. Repair was made by replacing all affected components with new, and we were billed even though vehicle was well with-in its original warranty based on service managers assumption that we (the operators) had somehow contributed to the failure. Telecom complaint to GM cust. Assistance, (file no, 1-299810112) returned same results. It is our contention that this critical part failed of its own Accord either through defect or design, and that we were extremely lucky that this happened in our parking lot and not on a highway at 55 mph. Vehicle operator has lost confidence in the safety of this equipment without a valid explanation and corrective action to a permanent remedy.

- Chardon, OH, USA