Would this pattern cause my humming sound from 60 down to 40? Not sure how to tell how much pad life is left? It only has 1000 miles and made the sound since 250. I’ve been easy on the brakes. One has a dark ring close to the center(left front wheel)?
Nothing looks too unusual to me there. I believe our brakes tend to benefit from occasional bedding, a few hard stops from high speed should bed a consistent amount of pad material onto the rotor, but others please chime in.
I would have thought your brakes should be fully "broken in" by the 1000 mile mark, but if you've been quite light on them they may need a little more time before they are normal.
What would cause the dark groove on one rotor? My fear of someone ragging on it and tracking it around Austin may be the opposite. Perhaps it sat idle and got grannied for a bit around town before I picked it up. Although tracking it around Austin is difficult when rush hour is basically sunrise to sunset. Speed limits are a lofty goal...even on the toll lanes
It could be a faulty bearing or if it’s from the back the diff. Discs look ok, if it’s dirt between pad and disc it would be a grinding sound. USA uses different pads to us. Take it in to get it looked at.
You don't need to do any brake bedding. The manual says to avoid hard braking during the "break in period" (same c. 600 miles of running the engine between 2K and 4K RPM, varying the RPMs during that period, i.e. not running at a prolonged RPM); during that time just brake normally (sanely ) and don't worry about it. If you have one rotor with a mark on it, you probably picked up some hard object that got wedged in there for a while. It won't harm your braking facility.
The marking that you see on the disks are form the machining process and will fade away with use. The pads have a lot of life left, at 1k miles they are still brand new.
The humming sound could mean that there is still some leftover coating on the disks that needs to be worn off. New disks come with a rust protectant coating form the manufacturer that wears off over time. If you ahve not done so please bed in your brakes as that process ensures that the coatings are removed from pads and rotors and also ensures the rotor does not accumulate pad material over time.
Took it out a bit ago on a twisty and hilly road. Smelled the brakes when I got back from lunch. Let it sit for an hour or two and the noise is 95% gone.
The pattern you see is as a result of a blanchard grinding. It is the only proper way to machine or resurface brake rotors because it does not leave a spiral and directional groove that lifts the brake pad off of the surface during braking. As far as markings on your rotors go, uniformity is the key. Random splotches and spots would be of concern. This rotor looks great.
) and don't worry about it. If you have one rotor with a mark on it, you probably picked up some hard object that got wedged in there for a while. It won't harm your braking facility.
