I have a Haro 357 that has been completely custom rebuilt. I noticed yesterday on taking the bike had for it's second DH run at Diablo there is a vibration that seems to be coming from the floating brake arm when the rear brake was brake applied hard with a loud noise like a horn. I'm running avid Codes 203mm frt and rear. It only happens if the brake is applied hard. Can anyone help shed some light on way this is happening? I was thinking the rear brake heated up from being on it too long causing the noise and vibration?