# New Bike - Front Disc Breaks Rubbing



## Perth (Apr 3, 2015)

I am having trouble with the front rotor rubbing on the Shimano disc break.

Everything is new and has not been ridden before.

Cayo 3.0 Disc
R685 Calipers
R685 Levers



When I insert the wheel into the fork the rotor enters the caliper.
The caliper break pads rub against the rotor while the breaks are disengaged.
I have removed the pads and see the ceramic pistons.
Using a plastic stick I have pushed the pistons back.
I have inserted a bleed block
upon rebuilding the rotors still rub








(Not my bike, but this condition)

What am I missing?

I have not bled the caliper (as I do not own the equipment)


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## robt57 (Jul 23, 2011)

Try a MTN XT or XTR skewer and report back...


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## Perth (Apr 3, 2015)

This is to straighten the rotor? (The rotor is new and is flat)

Can you link me to the product, when I google "XTR skewer" I get Quick Release skewers, and my bike uses a through axle system.
Video: Hands-on with the new Focus RAT (Rapid Axle Technology) thru-axle | road.cc


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## Mike T. (Feb 3, 2004)

It's a "brake" - B-R-A-K-E.


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## wgscott (Jul 14, 2013)

New bike? Make the shop fix it. Or just try re-centering the caliper. Don't bend the disc. Also make sure the axle is properly seated in the fork, as a wee misalignment can do this.


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## jfaas (Jan 31, 2014)

Mike T. said:


> It's a "brake" - B-R-A-K-E.


I'm glad I'm not the only one.


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## Randy99CL (Mar 27, 2013)

jfaas said:


> I'm glad I'm not the only one.


HA! Bugs me too.


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## Mike T. (Feb 3, 2004)

jfaas said:


> I'm glad I'm not the only one.


For about ten years I was the owner/keeper/writer for the Magura Cult mtb disc brake website and the "alternate" spelling for BRAKE got to be like the sound of fingernails on a blackboard.

The smartarses would come back with "Your brakes broke? OMG". Not me though!


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## tlg (May 11, 2011)

Mike T. said:


> It's a "brake" - B-R-A-K-E.


You mean the disc's aren't broken?


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## Mike T. (Feb 3, 2004)

tlg said:


> You mean the disc's aren't broken?


I'd give you a couple of slaps for that one. I used to work with a guy who used 's at the end of *every* plural word. I can't remember what he did with possessive words as I couldn't get over the plethora of 's in his training bulletins. Ooops, bulletin's.


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## Randy99CL (Mar 27, 2013)




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## Perth (Apr 3, 2015)

I am sorry for the misspelling of brake. I did take 2nd grade grammar and know the difference. I was typing and didn't think.

*But my real issue is the fact my disc rubs the front caliper.*

_I wish people had attempted to help me with my bike issue and not my English.
_


I pushed the pistons back, but they don't go all the way in. One side protrudes 1-2mm even after squeezing them back in with a plastic prong.
The bleed block fits with no wiggle room between pistons.
I attempted to recenter the caliper
I did not buy the bike from a shop.
I have ordered a bleed kit and will attempt to relieve pressure tonight. so the pistons might retract further?
The rear wheel with the same Shimano RS785 and Ice Rotor has no rub issues.

Or I can take to a LBS and get it looked at for $45


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## TricrossRich (Mar 26, 2014)

Have you simply tried moving the caliper on the mounting posts?


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## Perth (Apr 3, 2015)

My calipers mount to the fork directly:


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## TricrossRich (Mar 26, 2014)

right... but I believe the holes in the caliper should be oblong, allowing some movement side to side, at that's how the brakes on my Tricross was.


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## Perth (Apr 3, 2015)

Yes and I loosened these and centered the caliper. Still rub. It seems to be related to the pistons (in my unprofessional opinion)


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## jfaas (Jan 31, 2014)

What method did you use to center? A good description of your centering process might give some insight.


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## Perth (Apr 3, 2015)

2 methods;

I loosened the connection to the fork and with the brakepads installed i clenched the break gently, while clenched i tightened the connection to the fork. - Did not work.

The other method I jammed business cards between the pads and the rotor, this too did not work.


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## Perth (Apr 3, 2015)

Status: took it to Lbs. Guy spent an hour, said he doesn't know why it is rubbing, will work on it more tomorrow.


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## jfaas (Jan 31, 2014)

I don't have any road bikes with disc brakes, so bear with me. On the Avid mtb brakes I have used, the mounting bolts had the little hemispherical adjustment spacers that not only allowed for the lateral adjustment of the caliper, but also for angular adjustment. Does the new R685 caliper allow for angular caliper adjustment so the disc will slide into the slot perfectly parallel with the pads (Even if the caliper mounting pad surfaces are not exactly perpendicular to the disc)?


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## Mike T. (Feb 3, 2004)

Throw a piece of white paper or card on the floor under the caliper and with all your powers, sight down between pad and rotor and see what's going on. See where the gap *isn't* and try to adjust the caliper to create a gap. This is after you have squeezed the lever a few time and spun the wheel.

Then apply and release the brake while you're watching the gap. What happens? If the pad doesn't retract then there is a problem. I'm not sure what the pad retraction mechanism is for your brake. Is it the "deforming seal" method? If so, then maybe the flexibility of the seal isn't sufficient and the factory needs to re-engineer the seal.

This you should give you some ammo for your investigation.


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## nhluhr (Sep 9, 2010)

Perth said:


> 2 methods;
> 
> I loosened the connection to the fork and with the brakepads installed i clenched the break gently, *while clenched i tightened the connection to the fork*. - Did not work.
> 
> The other method I jammed business cards between the pads and the rotor, this too did not work.


Although what you're doing is not specifically wrong, the lack of detail in your description tells me you probably didn't do it correctly either.

1) Using the red pad spacer block, get the pistons to the correct gap. Also make sure the brake pad spring clip is correctly seated on the edges of the pads before mounting the wheel.
2) Loosen the bolts just enough so that you can wiggle the caliper.
3) while holding the brake lever tightly, use your other hand to wiggle the caliper more. This settles it into place on the washers and lets the rotor's springyness center it.
4) tighten each bolt just a little bit at a time, getting them first 'close' then 'snug' then 'tight' then 'torqued'. This prevents the turning of one bolt from causing the caliper to move a bit as friction between the washer and bolt head creates a torquing moment on the caliper's mounting tabs.
5) Now get an angle of view that lets you eyeball the gap between rotor and pad and spin the wheel gently. If you see the rotor moving left/right the rotor isn't true. Use a Park DT-2 or crescent wrench to gently straighten the rotor so that the gaps between the rotor and both pads remain uniform as the wheel rotates.


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## rcb78 (Jun 15, 2008)

I wouldn't be surprised if the PM faces need to be, well faced. But like others have said, it's all in the setup. The theory is easy, execution is something else entirely.


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## 92gli (Aug 27, 2009)

I believe that this will be fixed with a proper bleed. Might be able to fix it by removing the caliper from the fork, opening the bleed port just enough to crack the seal, and pushing the offending piston all the way in. These brakes are installed pre filled with fluid at the factories and the quick coupling they use for the lines adds some possibility of too much fluid. Had you bought the bike at a shop, they probably would have bled them.


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## 92gli (Aug 27, 2009)

jfaas said:


> I don't have any road bikes with disc brakes, so bear with me. On the Avid mtb brakes I have used, the mounting bolts had the little hemispherical adjustment spacers that not only allowed for the lateral adjustment of the caliper, but also for angular adjustment. Does the new R685 caliper allow for angular caliper adjustment so the disc will slide into the slot perfectly parallel with the pads (Even if the caliper mounting pad surfaces are not exactly perpendicular to the disc)?


Shimano doesn't use that crap, thank goodness.


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## Manning (Jul 8, 2010)

Might have a drop or two too much oil in the system. A buddie's mtb had that problem with brand new brakes. The pistons simply couldn't retract.


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## Perth (Apr 3, 2015)

Sorry for a lack of an update over the weekend.

the LBS worked on it for 5 hours Friday. Said he had never had an issue with Shimano hydraulic breaks and that this was a new issue. 

He got it 95% better but said the mounting location on the fork left him with out a way to get it 100% true. He said with a few rides and breaking I would wear the pad enough to give it clearance and have no rub. The rotor was true, and not bent.

His fix method involved adding a small spacer to the top attachment hex bolt. See below. He seemed to think this added mm helped.








Even with all the labor invested he only charged me $20, and was super nice about it.

I rode sat and sun about 50mi total and it didn't rub, but i did get a some squeaking feedback during large downhill spans where I braked often.


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## rcb78 (Jun 15, 2008)

If messing with the mounting face made it better, then ask if they have a post mount facing tool and did they use it? This is a pretty common thing to deal with if you recognize the symptom, and it's probably not the brake, it's the fork.
If they did all that and still nothing, then they're missing something...


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## Mike T. (Feb 3, 2004)

Perth said:


> I braked often.


At least be consistent and say "I breaked often".


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## Perth (Apr 3, 2015)

Mike T. said:


> At least be consistent and say "I breaked often".


I actually typed brea.... then backspaced.


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## OldChipper (May 15, 2011)

But I bet you have great modulation though, right?  Seriously, with rim brakes, this would be a 2 second fix. Anyone want to tell me again why disk brakes on road bikes are so wonderful?


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