CLEANING HYDRAULIC BRAKES

[musicbooks]

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]

For the sake of a fiver or so, you may as well get some disc brake cleaner.

Muc Off is a good brand - the size of the tin means it should last for years.

http://www.halfords.com/cycling/tools-maintenance/cleaning-lube/muc-off-disc-brake-cleaner-400ml

It will probably do the job, although disc brakes do tend to squeal now and again, however you look after them.

 

[Wicky]

As suggested use brake cleaner and also check how much remaining material is on the pads... as they can get crunchy when very worn down.

 

[musicbooks]

As suggested use brake cleaner and also check how much remaining material is on the pads... as they can get crunchy when very worn down.

They can't be worn down.. they are brand new

 

[musicbooks]

Thanks folks, I'll give it a go

 

[dan_bierk]

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]

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

 

[musicbooks]

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.

No.. only at low braking speed

 

[awol]

Since you say they are new, I wonder if they did not bed in properly. I would brake cleaner the discs and pads and lightly skim the pad surface with fine emery to remove the very top surface and basically take them back to new pad material, then bed them in following something like this

http://www.bikeradar.com/gear/article/workshop-how-to-bed-in-disc-brake-pads-31337/

 

[D C]

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.

 

[musicbooks]

Thank you everyone.. All very helpful

 

[awol]

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]

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.

 

[D C]

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]

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]

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.