Rubbing Disc Brake.

[Venod]

For a few months now I had noticed a slight rub on the rear disc brake when wheeling the bike, it was very light and I only noticed it because of a slight noise as it rubbed.
I had slackened off the calliper several times and applied the brake and re-tightened it, but it was still there, the disc had a very slight wobble to it so careful use of an adjustable spanner straightened it but it was still there, it wasn't slowing me down but it was annoying while moving the bike about.
Today I completely removed the calliper for a better look, nothing obvious, but to my surprise when I turned the wheel without the calliper attached the noise was still there !
So I stripped the rear axle and applied a smear of grease to the seals, on re-assembly the noise has disappeared, result no more annoying noises.

 

[ColinJ]

I am doing up my old mountain bike so I can get back into riding off-road. I put one new disc brake on and got the same kind of noise that you had but this one really was coming from the brake. I couldn't get rid of the noise by the usual slacken/brake/tighten routine. I took a very close look at what was happening and it was obvious that the calliper assembly needed to move over very slightly. I used some very thin washers as spacers to achieve that, then redid slacken/brake/tighten. I now have a very powerful brake which does NOT make a sound until applied!

 

[figbat]

More than once I have chased down an annoying noise, absolutely convinced it was one thing and then finding it was something else.

1. MTB - squeaky bottom bracket; started when pedalling, stopped when freewheeling. Removed, cleaned and greased the BB, no change. Turned out to be the freehub/axle assembly.
2. Motorcycle - classic valve ticking; checked clearances, all good, replaced the cam chain tensioner, no change. It turned out to be a leaking exhaust header gasket.