The rear hydraulic disk brake sounds like that about half the time ... not squealing at all, just scraping. Bike is 2 weeks old 300km with lots of braking.
Is that a sound that is recognizable for a likely diagnosis?
I just removed the caliper and wiped the disk with alcohol and wiped the pads with alcohol on coffee filter wrapped on a card and it's quiet now. Maybe a grain of sand or something got on there.
oil or contamination on the pad - symptom = poor braking - fix: solvent wipe down using denatured alcohol which leaves no residue.
spot of grit/sand in the pad - symptom =odd noise, grating sound - fix: remove pads, inspect and pick out particle with small sharp pick, sand pads smooth on 400 grit sand paper on flat metal surface or replace pad if near end of life. Inspect rotor for scratch or gouge...do not try to resurface. replace if needed
brake pads not properly worn in resulting in glazed surface - symptom loud squeal or musical tone - remove and sand off glaze using technique in #2
For proper brake pad break in start on a steep hill. Head down at good speed, brake hard for 2-3 seconds then release, speed back up, repeat four or five times. That's it. DO NOT ride off with a bunch of normal, gentle braking. They need to be worn in hard and fast but not long as they will then overheat and glaze requiring a sanding.
