Road disc brake very noisy and resonating

[murray]

Anyone any idea what would cause the following on a new Tarmac disc which had only done about 100 miles? Basically brakes started getting noisier and noisier and resonating. Was worse when going slowly up hill, noise was horrendous. Could stop it by either riding out of the saddle and putting weight over front wheel, pulling brake sharply (stopped it for about 100 m and then back again) or by keeping the brake on gently all the time. Totally ruined the ride and my legs as the climbing was hard enough without doing it with brakes gently applied.

[Piginapoke]

Sounds like something rubbing. Take the pads out, clean and inspect.

[murray]

Are you sure that would cause it? I had wheel off numerous times and couldn’t see anything in there. When wheel went back in it rotated freely then it started again. This went on for about 170 miles.

[murray]

Is it possible for there to be too much hydraulic fluid to have been added causing the pistons not to retract properly?

[Mr Ted]

Slacken the caliper mounts by half a turn, pull the brake hard on and re-tighten the caliper mounts.

[murray]

Did that three or four times, no difference. Dropped it off at bike shop for them to look at.

[lufbramatt]

murray said:

Is it possible for there to be too much hydraulic fluid to have been added causing the pistons not to retract properly?

Yep, the Avid Elixirs on my my Trek Fuel suffered with this when brand new. Fine for the first 7-8 miles of riding, then the fluid would heat up and the pads would start dragging. Undid the bleed screw and released a tiny bit of fluid and all ok.