After several months of front-end shimmy or wobble under light to moderate (but not heavy) braking, I changed out the front rotors. Runout was not bad, and adjusting the hub bearing preload did hot help, but a secondary inspection revealed what appeared to be light pitting on the rotor surface, but mostly in straight lines, just barely enough to start to catch a fingernail.
Since the new rotors solved the problem, I attribute the pitting to actual cracks in the rotors. Anyone ever seen this before?
I normally don't overheat the brakes, don't overload the car, and don't stand on the pedal at a stop after hard braking.
The rotors are not cracked. The line you see is where it had rusted after setting for a few rainy days or a week. If you notice in the last picture there is the outline of a brake pad a little over from the line (to the left). The pads have a 1/8" cut from top to bottom. Maxi brake rotors are not that thick (compared to some other cars) and can warp fairly easily (to my experience). If someone else drives the car it may have happened that one time? There is also the possibility that in stop and go traffic in the city? or on a long downgrade? Have the rotors cut, and I believe you will be ok after that. (sometimes rotors can warp a little after getting hot initially, a bit like a piece of wood can warp after it is cut from a tree).
Surface WAS rough, would have been borderline or failed spec after cutting, so I simply replaced them.
I agree the brake rotors and suspension components are on the "light" side, but I also enjoy that the lightness makes the car feel more nimble compared to others of its size.
