Front Suspension Wheel Bearing problems of the 2000 Ford Mustang

Rear axle bearings and axle shafts prematurely failed. First occurance was at 34,000 miles under manufacturers warranty. Dealer replaced carrier bearings, wheel bearings and axle shafts. Axles and bearings failed again at 46,000 miles, after warranty expired. Dealer contacted Ford motor company and Ford elected to replace bearings and axles again under warranty. Now at 90,000 miles the bearings and shafts have failed again. Dealer is evaluating the problem with Ford and I am waiting for a solution under warranty due to either a manufacturing defect or design defect. I am worried that the bearings will seize and cause an accident.