Rotor rub : what do...
 

[Closed] Rotor rub : what do you do when you've tried everything ?

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Fitted some new wheels today and both rotors rubbing. Undid caliper bolts, pulled brakes and tightened again : this has no effect.

Tried and checked if rotors out of true so I dicked about with them but to no avail.

What's my next step please ?


 
Posted : 10/08/2017 10:32 pm
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Check the pistons have been pushed all the way into the caliper before re-positioning it over the rotor.


 
Posted : 10/08/2017 10:33 pm
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Is it only rubbing on one section of the rotor or all of it?
Both pads or just one?


 
Posted : 10/08/2017 10:47 pm
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Don't align them by slackening the bolts and pulling the brakes. Align them, with pads pushed fully retracted, so that the rotor is central in the calliper - view with a torch behind to check. Then slowly torque up the bolts, checking that rotor remains on centreline of calliper.


 
Posted : 10/08/2017 10:58 pm
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Is there a washer between bolt and caliper? If there isn't every time you tighten the bolt it'll slightly walk the caliper and you'll get rubbing.


 
Posted : 10/08/2017 11:38 pm
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Don't align them by slackening the bolts and pulling the brakes. Align them, with pads pushed fully retracted, so that the rotor is central in the calliper - view with a torch behind to check. Then slowly torque up the bolts, checking that rotor remains on centreline of calliper.

This, although I do it with the pads pulled in, to take into account any uneven action on the pistons. Either way, I've found setting the calipers by eye to be more accurate and almost as quick to do as the old "loosen and pull" approach.


 
Posted : 11/08/2017 7:18 am
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iainc - Member

Don't align them by slackening the bolts and pulling the brakes. Align them, with pads pushed fully retracted, so that the rotor is central in the calliper - view with a torch behind to check. Then slowly torque up the bolts, checking that rotor remains on centreline of calliper.

This ^^^

Don't use the 'slacken off then pull the brakes trick'. Also you a light source behind to check as above.


 
Posted : 11/08/2017 8:09 am
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There's quite possibly too much fluid in the brakes and the pistons aren't retracing far enough. No brand is immune to this IME. I usually take the wheel out, crack the bleed nipple on the calliper, and simultaneously push the pistons apart with a screwdriver. Do this carefully and slowly and just let literally 2,3,4 drops of fluid out. Refit wheel and have another go. Usually works. Avid/SRAM brakes are the worst for this, though, obviously.


 
Posted : 11/08/2017 8:31 am
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Hayes disc brake caliper alignment tool also takes guess work and faff out of the equation..


 
Posted : 11/08/2017 8:48 am
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Thanks everyone - using the visual method has helped - and in particular it has helped spotting the bends in the rotors !!!

95% of the way there now which will have to do - I'll probably buy new rotors as mine have been bent so much and in so many directions...

Although I realise new rotors can come pre-bent !!!


 
Posted : 11/08/2017 11:06 am