the guy at your dealer wants cover his ass.回复：Believe it or not,

it is possible the guy didn't install the pin, the shoe hold-down spring and cap correctly and some of those part loosing while your wife is driving and the brake shoe slips out from its groove and sticks the brake drum that would definitly cause the wheel lock suddenly. the shoe off its specified position will be like a wedge sticking between the cylinder and the drum.