TwoHemis said:
Dealer says front brake rotors are warped (which I believe based on vibration/noise when braking) at 16K miles but calls it a "comfort" issue rather than under-engineered brakes, and wants me to pay to have the rotors resurfaced. Is this reasonable, or a rip-off?
I experienced warped rotors on a car 5 years ago at only about 4K miles, and the dealer gladly fixed the problem for free, as it was a problem common to that vehicle.
On a few other cars, I've experienced warped rotors after 30K miles and gladly paid for resurfacing as just normal wear & tear.
Just seems like I shouldn't be shelling out cash to repair a 10-month old car.
Before you pay anyone any money to do anything to your rotors, try rebedding the brakes. Follow my instructions here:
http://www.zeckhausen.com/bedding_in_brakes.htm. This will often cure what you are calling "warped" rotors.
The real problem is that you have uneven pad transfer on your rotors resulting in thickness variation, not runout. We see this all the time. The symptom is brake judder and most people have a mental model that includes excessive runout (or "warping") of the rotors. This incorrect mental model is only strengthened when replacing the rotors or turning them on a brake lathe makes the symptoms go away. Think about it. If the problem is pad transfer resulting in thickness variation, then replacing the rotors or turning them will
also make the problem go away. But the lack of understanding of the root cause results in procedures that encourage formation of new deposits and recurrence of judder. Thus the additional myth that turning rotors encourages them to warp faster!
Read this tech article and see if it makes sense:
http://www.stoptech.com/whitepapers/warped_rotors_myth.htm
If that doesn't convince you, then ask yourself why this technique for curing brake judder works like magic for all my racing customers:
http://www.zeckhausen.com/avoiding_brake_judder.htm
I will often run into someone who
insists the problem is warped rotors. If that person has a big brake kit or a car with very expensive rotors, such as the BMW M3 or M5, I will install a set of Hawk Blue track pads and tell them to drive around for an hour on the street, using only light to moderate braking. At the end of the hour, the "warped" rotors are fixed! If they were really warped, there's no way an abrasive race pad would fix them. What happens is that the Hawk Blue pads chew away the uneven pad transfer material. They polish the rotors clean in very short order and the judder is gone. That experience is usually the breakthrough required for my customer to give up on the false belief that warping of rotors is a common occurrence.
The practical take-away from all of this is that there are steps you can take to prevent brake judder. Proper bedding of the brakes, as described in the link at the top of this post, will put a smooth, pad transfer layer on the rotors. This provides all the benefits described in the article, including quieter braking, longer rotor life, and better pedal feel. But most importantly, it protects you from getting
partial transfer layer and the resulting build-up of material at the leading edge of this partial layer, ultimately causing judder. By bedding the brakes and occasionally doing some late, hard braking to keep that transfer layer maintained, you will avoid the curse of, what so many people incorrectly refer to as,
warped rotors.
