Disc Brake Noise

[Shoogle]

This has been annoying me for years. The front disc brakes rubs, or I'm asumming it rubs, and makes a noise like a wasp. I've tried googling it and searching on here but I'm still no further forward. The rotor seems flat and running true. I've tried loosening the calipers and re-tightening with the brake lever held on. Even when the pads wore out and I renewed them it's still the same. I've tried loosening the calipers and then tightening them when I can see space next to the pads on either side of the rotor. At low speeds there's no noise but the faster I go, the louder the noise. They are Shimano hydraulics-BR-M485. The rear brake is fine; no noise. Can anybody help?

[Brucey]

apologies if this is all obvious to you but ;

-have you got the centreing spring in place?
-when you release the brake, do both pistons retract equally?

sticky pistons can retract unequally or just not far enough in total. They should both move, and move equally whenever the brake is applied; compare what the front brake does with the rear.

Do be sure there isn't a fluid leak; I guess you would have noticed if you have owned the brake for a few years.

Any time the brake is on it will make some noise; if the running clearance of the pads is too small (even on just one side) then it may make a noise all the time.
hth

cheers

[thecycleclinic]

Also make sure the disc is centered between the pads. If the disc flexes when the brake is applied then this can result in some noise.