CLEANING HYDRAULIC BRAKES

musicbooks

Esteemed Pedelecer
Oct 10, 2007
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What's the best method of cleaning hydraulic brakes. My front brake is moaning and grinding with a very high pitched squeal at low speed.. (not unlike a few friends of mine) :)
 

RobF

Esteemed Pedelecer
Sep 22, 2012
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dan_bierk

Just Joined
Dec 9, 2014
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Is the squealing when you aren't applying the brake? I recently had this problem and discovered that the pads were misaligned despite being brand new, might want to check that as well.
 

flapajack

Pedelecer
Aug 4, 2013
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Mine always squeals (loudly) when wet - especially after a wash when I go for a quick air-dry blast. Is that normal?
 

D C

Esteemed Pedelecer
Apr 25, 2013
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lightly skim the pad surface with fine emery to remove the very top surface and basically take them back to new pad material
I find it helps to stop squeal if I give the pads a little toe in by pressing slightly harder on the trailing edge of the pad as I skim.
This is the only way I can get new pads to stop squealing which does drive you mad even if it saves you needing a bell!
I still get a squeal if wet till I've used them a couple of times.
The link that awol posted is very good.
Dave.
 

awol

Esteemed Pedelecer
Sep 4, 2013
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I find it helps to stop squeal if I give the pads a little toe in by pressing slightly harder on the trailing edge of the pad as I skim..
A great tip, I will try this next time.
 

RobF

Esteemed Pedelecer
Sep 22, 2012
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To get toe in - not sure it's called that on a disc brake - you will need to skim the leading part of the pad more than the trailing part.

This is a rim brake, but if you substitute the rim for the disc rotor the point is the same.

images.jpg
 
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D C

Esteemed Pedelecer
Apr 25, 2013
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To get toe in - not sure it's called that on a disc brake - you will need to skim the leading part of the pad more than the trailing part.

This is a rim brake, but if you substitute the rim for the disc rotor the point is the same.

View attachment 10103
Thanks Rob, we both mean the same thing but I should have worded it better, I did mean the edge facing the direction of rotation, facing the back of the bike.
Dave.
 

RobF

Esteemed Pedelecer
Sep 22, 2012
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Years since I've tinkered with rim brakes, but I believe you can get toe in on some by adjustment, which of course you can't do with discs.

The rim brakes on Bromptons were famously average until a lever redesign a few years ago.

I have the older type which have never given any bother, although I can confirm stopping power is less than spectacular.
 

awol

Esteemed Pedelecer
Sep 4, 2013
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Couldn't wait to try it, I've just stripped my brakes down to clean and lightly sanded the pad just as DC states above, not tested them yet though but this made me realize they must be put back into the correct side for the toe-in to be correct, it also made me realize that toe-in can already be shaped onto wearing pads and thus if removed for cleaning they too must be put back into the same side they came from.