Has anyone had issues with harmonic/ringing (Not howling) on Shimano M8000 Brakes with IceTek Rotors? I have a 180mm IceTek Rotor and an M8000 Caliper (Original J04C Metal Pads) on the rear of my Specialized Camber Comp. When I start to descend down a hill and hit the brakes a few times I start to get a ringing/whopping sound from my rear brake when I release the brake(only on the Rear Brake). This has been happening for almost a year since they were new. Screws are Torqued, Pads bedded.
I’ve had similar ringing problems but with Tektro brakes. It also only affected my rear brake. I would clean the pad and rotor with isoprobyl alcohol and it would go away for a while but always come back in some form. Eventually, I replaced the pads and didn’t have issues after that. I’d say cleaning your braking surfaces could be a first step, followed by replacing the pads outright. If you have problems beyond that then I’d contact the manufacturer and/or retailer because that sounds like a major job. I know sometimes the pads can get glazed over from heat or small bits of dirt/chips of rock can get lodged in the pad surface which make all kinds of noises as it slides against the rotor. If changing the pads doesn’t help, I’d say that’s a problem only the manufacturer can handle.