First thing, there is no such thing as warped rotors. Pulsing/shimmy can be caused by a lot of things. Uneven brake pad deposits on the rotor, rust spots on the rotor (check the back side of the rotor), lateral thickness variation, excessive wheel bearing run out or excessive run out on new or used rotors. Throwing parts at a problem is a good way to spend ten times what it would cost to inspect and analyze the brakes to find out what is causing the shimmy. Uneven brake pad deposits may be taken care of by going out and doing about 20 hard stops from 25 mph to 5 mph without locking up the wheels.
Bill
It's ignorant to say rotors never or can't warp. I see it all the time. I would call lateral thickness variation warping. And the cure is to replace or turn the rotors.
Excess wheel bearing run out will cause a low brake pedal, not a shimmy, and I've never seen any kind of pad deposits on a rotor. Just saying...
Sounds like someone is a paid mechanic....lol I replaced the rotors yesterday, no more shimmy. I purchased the high end rotors and they where obviously higher quality than GM put on stock. While I was at it, I had the old ones checked out by a friend of mine...they where warped, severely. So yes they can warp, no "Special mechanic inspection for $$$$" needed.
The rears can warp too.
There is nothing special about jacking up the car, spinning the wheels and applying the brake lightly to see which one is actually causing the problem.
If you did not do that, then you just got lucky.
Guys, let's all be civil, especially you, Rukee.
Brake discs DON'T warp!
That link above is to a site that has more knowledge than anyone on this forum (to the best of my knowledge) about brakes. And Bill was absolutely correct when he said that rotors don't warp. (Disclaimer: Read the article. At the top it says they can, but only if installed incorrectly, not due to braking.)
If you have a real desire to learn and understand how things actually work it will make sense and you'll be miles ahead of all the others who say the oft-repeated phrase, "the rotors are warped".
If you want to comment, take the time to educate yourself, and take the time to show some respect to others who share truth with you. Bill did just that and his reward was a comment inferring he was ignorant.
If you click on my screen name and find other posts I've made you'll see that I'm not always right. The difference between me and some others is that I can admit when the information shared with me is a better understanding than I had coming in, and I leave with a better understanding. How can any of that be bad?
If you choose to stay in the stone age, go ahead, but please don't start spouting opinions that you haven't researched or for which you have only partial knowledge.