I recently found a bicycle used by a relative which seemed to be in good shape. However, I found that the hydraulic disk brakes make a loud squealing sound towards the end of the stopping distance. After watching videos on the same problem, I've tried sanding the pads, Sanding down the disks and even bleeding the brakes, in that order. Nothing has worked. Just today, I bought new brake pads and installed them but... The squealing is still there!
I don't think the disks are out of alignment becuase they don't make the typical periodic noise of misaligned/ bent disks.
What should I try? Should I just wait for the new pads to break in?