Clicking brakes... Grrr

[airbrakes]

I seem to have a small but very annoying problem with the front brake on my bike. The disc is making a loud clicking nose as it rotates, this noise disappears when the brand is applied, even by the very tiniest amount. I don't get how it can be catching on something, as if rotates as freely as normal.
Can someone please help before it drives me nuts?

[barker22]

You tried the pad spring? if it is ever so slightly bent the metal may be touching the disc and clicking on each hole of the disc?

[marting]

My hybrid does this when the caliper isnt adjusted correctly or the pads are too close to the disk. The pad gets pulled away from the magnetic part of the piston and then falls back onto it, clicking back into place.

[marting]

...that assumes your pads arent held in with clips and are magnetic.

[TheLemming]

Had the same issue with mechanical discs.
Again a setup issue, i'd knocked one of the pads with the disc when changing a wheel. The fix was remove and replace pads and realign.
Can also be caused by the wheel being very slightly out of alignment in the dropouts, so the disc is at a very slight angle etc.

Wouldn't surprise me if a warped disc could show the same symptoms as well - although that's easily fixed

[airbrakes]

Thanks guys,
The brake is a self adjusting hydro disc with the pads retained by a bolt, so I gess that just leaves the retracting spring to examine to see if it is bent as suggested

[Smartboy]

Slighly out-of-true disc perhaps?
Wheel not quite sitting in the drop-outs correctly perhaps?

One of my bikes did this once. Turned out the rotor was hitting the body of the caliper once every rotation.
Cured by re-seating the wheel and then loosening the caliper retaining bolts and re-centering the caliper relative to the rotor.
Think the caliper got a bash during an un-planned dismount into the undergrowth one day which must have knocked it out of alignment very slightly.