[Closed] Disc brake rubbing help please.

To centre the brakes I would loosen the caliper a touch, close the brakes by pulling in the lever, then re-tighten the caliper.
If the brakes are still rubbing perhaps the disc is warped and will need straightening.

Presuming the rotor is true, and the caliper is post mount, loosen the mounting bolts so they grip slightly and manipulate the caliper so that the rotor runs in the centre of the slot, or close to it, without rubbing.

This may be difficult to achieve if you have a sticky piston. The answer to a sticky piston is different to the answer I am giving you.

If anyone answers "hold the brake lever tight when the caliper mounting bolts are loose, and tighten while holding the lever all the time", they are wrong, but it occasionally improves things - if you are lucky enough for both pistons to be totally free and centred.

The Hope website often has videos regarding such jobs, and are applicable to most hydraulic brakes.

If anyone answers "hold the brake lever tight when the caliper mounting bolts are loose, and tighten while holding the lever all the time", they are wrong

Works everytime my arse. Never had any of the two sets of Avids do it and neither me Hope.

IMO you have to do it by sight and spinning the wheel. Ensuring a gap at all times, finickey little job but worth the extra few mins sorting it properly. Pads should not even slightly touch the disc when not applied.

I find the Loosen > Brake on > Tighten method rarely works.
I use a torch held on the far side of the caliper as I look down the gap between the disc and pads helps to get the two gaps even.

Doesn't Work [s]everytime my arse[/s] for me, but I can't comment on other people's experiences. Never had any of the two sets of Avids do it and neither me Hope.

Don, I work as a cycle mechanic. Not boasting or anything, but it does mean I do this particular job frequently. I'm only saying what works most often, and it isn't holding the lever on.

My objection is the "wrong" bit. It works for me and I'll continue to use it until it doesn't work and then look for another solution. You are now saying that you do something that works most often which means there are altenatives. You also want me to believe that all cycle mechanics know what they are doing and are good, which is not true.
I am also not alone in this solution.

always works for me and my hopes. never with the stoopid avids i got rid of in 5 days 🙂

jedi, my arse, you're wrong! 😈

lol 🙂

what waderider said, also the torch from behind as mentioned helps too. Shimano brakes on 3 bikes.

I am also not alone in this solution

@ scaredypants 😆 😆 😆 (not sure why though 😕 ).

The "hold the brakes on while tightening the calliper mounts" works if you are careful with the tightening - tiny bit at a time alternating between the two bolts with a ball-ended allen key. On Avids and Formulas and Shimanos that I have worked on.

If you give the bolts a quick turn then the calliper moves about and you get a fail.

That is what I have found and I have done a few.

I've only had Avids and not found the "lever on" method to work.

Bike upside down, looking through/either side of the disc to a well lit piece of light coloured paper or flooring to check the gap and careful bolt tightening has always been the most effective method for me.

"loosen bolts, lever on, tighten bolts" sounds much easier. Maybe I should try Hopes...

fill your LBS mechanic with cake and crisps from lidl's and tell them how great thier bike is works great for me. 😆

don simon - Member

Except when it works all the time, which would make you wrong.

As another person that works in the trade, got to say that this method is the least successful method of centring troublesome disc brakes...

<anecdote> it worked for me </anecdote>

Mine squealed for [i]months [/i]whilst riding along and it drove me round the twist. Loosening the bolts, locking out the lever and nipping it up again fixed it permanently.

Granted, anecdotes are just that, and I'd probably have had better results / a 'best practice' solution by sighting it and aligning manually. However, as a quick and dirty fix, it was close enough for me.

Mine squealed for months whilst riding along and it drove me round the twist. Loosening the bolts, locking out the lever and nipping it up again fixed it permanently.

why did you ride like that for months without trying the tried and tested method?
in my experience it rarely (if ever) works perfectly. works ok, maybe, but usually not.
Sighting by eye is best method. If you get lucky with the old 'loosy,brakey,tighty' method then cool beanz to you.

Rochey, why don't you try the brakes on and tighten method first as it takes not 5 mins? If that doesn't resolve the issue go to the sighting method.
Surely the objective is to help the guy and not demonstrate that you are more right. FFS! You'll be telling me I'm wrong for overtaking middle lane hoggers on the left, next! 🙄