Please Delete

 

I'd place my money on warped front rotors.

 

Indeed warped front rotors. I had the same exat problem with a friends Alero. We changed the rear rotors, and pads all around, and I cut the front rotors. We changed the front rotors, and it fixed the problem.

 

When replacing the rotors it is important to note that they have three different size holes cut in them where they sit on the hub. When looking at the hubs you will see where rust has built up where exposed from the holes. If the new or ols recut rotors are'nt put back on the same way, or you have'nt cleaned off the buildup from the holes, this will cause the rotor to not sit flush against the hub and it won't run true cusing a shudder during braking at high speed.

 

I had a problem kind of like this a while ago. I got a shudder if I hit the brakes kinda hard. I had all four disc re-surfaced and I installed carbon-ceramic brake pads. That fixxed it all up.

I would have to say its gotta be one of the discs making it shudder. I can't think of anything else that would make it shake like that. Your right, its not a bearing because that would get louder and louder the faster you went.