Argh Stop Squealing - Brake Help

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Argh Stop Squealing - Brake Help

26 posts & 16 voices | Started 1 year ago by RDL-82 | Latest reply from RDL-82

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RDL-82 - Member

Hi all,

Need some advice to help shut up my brakes and cure the headaches and funny looks.

Recently changed my pads to sintered, did one ride in the snow where they behaved faultlessly, great bite and no noise, got home and didnt touch bike for two weeks due to other stuff getting in the way.
Went for a ride the other day and they are squealing like pigs in pain (both ends).
Removed everything and pads were glazed so i rubbed them down with some 180wet and dry and cleaned everything up, went out to bed them back in and squeal squeal squeal, pads out and they are glazed
Have rubbed the pads down again and also lightly rubbed the disc down as that was starting to look pretty glazed as well. Have cleaned it all up, but not tested it yet, but assuming that doesnt sort it what else can i try?

The brakes were bled before the new pads went in (pads stayed in packet) and all was fine for that one ride. The brakes are XT M775 with sintered pads and the new style XT 6 bolt floating rotors.
I've always used Resin/Organic pads previously and never had a problem so im a bit stumped.

Has the cold ride then total lack of use ruined them? The bike is stored indoors in the same cupboard as all the heating system so it gets pretty warm, that have anything to do with it? I'm probably clutching at straws with that as its a new problem.
Was going to just order some more Resin but dont want to have the same problem.

Cheers

Posted 1 year ago #
oneoneoneone - Member

sounds silly but are the pistons free from dirt/dust/grease??

that my help

Posted 1 year ago #
parkesie - Member

just a drop of oil on them.

A more serious suggestion is make sure all surfaces are clean double check and the calliper alignment and last just a light smear of copper grease on the back of the pads.

Posted 1 year ago #
TandemJeremy - Member

Are you sure the pads are glazed> they should have a s smooth sort of satin look on the surface. True glazing is from overheating but they can get polished when cold as well.

Some combinations of pad and disc just squeal. My guess is they are not getting hot enough to work properly but its only a guess.

Things to try are a tiny smear of copaslip on the back of the pads, check calliper alignment, last resort is to file a chamfer of a mm on the leading edge of the pad

Posted 1 year ago #
RDL-82 - Member

Hi, have cleaned calipers, and pretty confident the pads never got oil on them when being bled, and i cleaned the discs before fitting the pads, plus there is that first ride where everything was fine.

Was thinking of putting a bit of copper slip on the back but the bcking plate has holes in it and i remember reading somewhere not to if that was the case. Have checked allignment and there is no rub.

Would say it was definately glazed, they were polished very smooth and tarnished? black, and ive got poor bite now.

Posted 1 year ago #
Militant_biker - Member

Are you sure it's not just because of the cold? All our discs were squealing away on Saturday on our snowy ride. They would shut up on the longer downhills, but most of the time it was like riding with a wedge of geese.

Posted 1 year ago #
RDL-82 - Member

Possibly just the cold, but even the downs couldnt cure it the other day.

Sorely tempted to just go back to Resin, as i wasnt even getting poor pad life out of them.

Out and about in Todmorden tomorrow so hopefully get them nice and warm, but if anyone hears a bike being murdered its probably me!

Posted 1 year ago #
elaine anne - Member

i will listen out for you then seen as i live in singletrack land !.. they squeek when wet anyway, dont be too bothered by the noise..you,ll end up listening for every noise on the bike soon :wink:...i was out in boggy muddy conditions yesterday on walsden moor and my brakes squeeled abit with the muddy terrain and melted snow/ice water....

Posted 1 year ago #
RDL-82 - Member

Its just really annoying, especially after 18 months of almost utter silence fromt the brakes...still not sure why i changed compound

Will see what tomorrow brings, and if all else fails i'll give CRC some more money.

Posted 1 year ago #
elaine anne - Member

well if i cant hear you i guess the brakes will be fine then.. i have organic up front and sintered at the back at the mo..lol.......
you havent picked up a mouse on your travels have you.

Posted 1 year ago #
RDL-82 - Member

Well if i have, its going to be sorry when i find it after all the messing about ive done

Posted 1 year ago #
superfli - Member

You could try putting a little copper grease on the back of them (piston side). It'll help deaden the vibration.

Posted 1 year ago #
Van Halen - Member

pad and rotor, gas mark 9 for 30 mins (when the missus is out)

might have picked up oil/crud from anywhere.

Posted 1 year ago #
elaine anne - Member

lol mr Halen ! really ? ahahah hmmmm chicken suprise tonite anyone..blame mr Halen if it tatses funny.... lol

Posted 1 year ago #
BoardinBob - Member

elaine anne - Member
lol mr Halen ! really ? ahahah hmmmm chicken suprise tonite anyone..blame mr Halen if it tatses funny.... lol

Yes, it works

Posted 1 year ago #
SamB - Member

Gas mark 9 fixed the squealing on my XT M765s. Definitely worth a shot before buying new stuff.

Posted 1 year ago #
m_t_b - Member

I have always boiled them but will try roasting them instead as always been unsure how effective that is... I guess they get hotter if you roast them.

Posted 1 year ago #
Speshpaul - Member

" a light smear of copper grease on the back of the pads. "

Don't, my work ob car pads but its not a good ideal on bikes.

Posted 1 year ago #
7hz - Member

I have Shimanos as well. I have also had intermittent problems with horrible squeak, no bite etc. I am having these problems at the moment.

This has happened over all types of pads.

I have a theory that what is causing this is salt. This time of year, we get tonnes of the bloody stuff on the roads, and it is going to get into the brakes.

Now, salt is added to washing up liquid, partly as a thicker, but also I believe to make the 'squeaky clean' feel to glass etc.

I think the same is happening to the brakes.

Try washing the brakes with plain warm water, give them a good rinse. Other than that, I haven't found any solution :-/

Posted 1 year ago #
JAG - Member

Most brake systems will have some noise at some time.

It's not usually much to do with glazing so much as just the size, shape and weight of the parts involved and the brake forces. I don't think sintered pads can glaze either - only organic pads have compounds which will evaporate off with heat (that's what happens when the pad glazes).

I think the change of pads is the main cause.

Things you could do:
1)change pads back to organic pads
2)put a chamfer on the pad mat'l (as per TJ)
3)ride and learn to appreciate the audible brake warning device.

Don't bother with Copper Slip - if it works it will only be short lived and the risks of grease on the brake pad surface etc... is obvious.

Posted 1 year ago #
james-o - Member

road salt has ruined all my pads recently, non-stop squeal on all types..

boil the pads in a pan for 5 mins, rub down with sandpaper, boil again, rub rotor down, sorted.

Posted 1 year ago #
RDL-82 - Member

Well i can confirm that Todmorden/Hebdens finest mud had no affect really.

So i think ill try the boil method some off you have posted and add a chamfer, also going to rebleed as they also felt pretty bad in that respect today, but that may be the pad/disc lack of bite whatever, or maybe its all in my head, but ill do it anyway, failing all that its time to spend yet more money i really cant be doing with it, its not the usual bit off squeal its a full on wtf my ears are bleeding, plus a general lack of confidence in the brakes is not present (in the head again no doubt) and thats not conductive to an enjoyable ride.

Time to fettle...cheers all

Posted 1 year ago #
elaine anne - Member

use the brakes less also... i just use mine very intermitent not full on when applied.
i also sandpaper my pads too alittle then clean.
in wet weather all brakes squeal-fact... theres no escaping until winter and salt issues have past.lol

Posted 1 year ago #
Oscillate Wildly - Member

if they are shimano xt m775 sintered pads, then there lies the problem!

simple solution goto superstarcomponents and buy the sintered pads on there = silence!

i had stock shimano sintered and they made a constant howling/squealling horrid noise no matter what the weather/temps etc rain or dry...

i swapped to shimano resin and they were pretty much quiet, but lacked bite in the wet etc and was getting through them at a fair pace

thought sod it try sintered superstar and low and behold they are silent in all but mega snowy/ mega wet conditions, and still have most of the life left in them after 3 months of pure winter mud/grit!

seriously, i thought it was a fluke with mine, as id used the superstar ones just in the back, which i was shocked how quiet they were, so i bought another set for the front and put them in, and again total silence in all but the very wettest conditions, which proves its no fluke!

soooooo if they are sintered shimano then take out, bin and swap for superstar!

Posted 1 year ago #
RDL-82 - Member

Im light on the brakes anyway, defo dont drag, dont even cover them - thatll back fire one day - had these brakes 18months and this is the only time theyve been bad, so need to figure it out, its bugging me now.

Posted 1 year ago #
RDL-82 - Member

Ha you try to edit your post and the forum dies all night...

I'm using Aztec sintered so it's definitely not dodgy Shimano pads. Going to re bleed them as well as they felt pretty spongy at times yesterday, so wondering if they are not biting enough and glazing/squealing/whatever.

I'll get there...eventually

Posted 1 year ago #