Spent ages getting rid of my rear squeal on the bike and after a new caliper different rotor and new pads i’ve sorted it…but just as the rear is fixed the front is going mad…Its not a wet weather squeal its a even when i push it in the house as soon as it grabs hi pitched scream…

I have Shimano MT51 rotors that say for resin only pads, having read loads of different opinions on that subject i bought some sintered ones…put them on and for 10 miles ok now they are back to screaming away…I took the rotor off and put on a smaller 160mm A2Z rotor which i gave a good sanding down before i installed…guess what exactly the same….I can’t see any oil lurking about..

The only other thing is i think the front might have gone funny (as it was always ok) after i had new forks put on….

Any ideas before I buy some new rotors and any suggestions on which rotors…

Discs are SLX by the way…

Thanks
Ant

does it get any better if you ride for longer ?

Hi

No worse its painful you must be able to hear me from miles away, Its not like a normal squeal its as soon as i touch the brakes it grabs and makes a noise like…hmmm maybe like metal on metal…The new pads were fine for 10 miles then after a technical downhill back to bad…dry weather as well…I’ve sanded the discs , the pads, different rotor , new pads….

Thought SLX were meant to be good…I’m not enjoying mine yet 🙁

thanks
Anthony

In my experience, sintered pads are always noisy.

I do live in the Alps, so they get harder use and get a lot hotter. Used to be fine back in the UK. But out here, sintered = noise.

Got a set of SLX and XT brakes on different bikes, running the standard finned pads. Have used the shimano alloy spider discs and superstar ‘floating’ with them and not a sound, wet or dry.

Not much use to you, but just saying that the SLX’s are good, worth persevering.

In my experience sintered pads often squeal.
If it happens when just pushing it into the house then the pads & disc must be touching, therefore the alignment must be out.
Have you heat cycled the breaks to bed them in?

often in dry weather you find sintered squeal a bit more, in the damp wet conditions are usually when my sintered dont squeal

and vice versa with organic, pretty silent in bone dry summer, and noisy in the wet

thats my experience with superstar ones anyways!

generally the sintered are quite quiet both F & R, but if you drag on a road descent or a long section off road thats when they will squeal, mine generally dont squeal when just doing braking bursts etc as your suppose to use them

in fact at cannock at the weekend they were completely silent throughout 25 miles of on/off quick succession braking

last night on a long road hill descent back to the finish my squealed on the front as id been braking pretty much all the way down the steep hill (guessing as they were getting really hot!)

I’d be blaming the sintered pads, rather than the rotors….

I use sintered pads and they do tend to squeal quite badly. Going back to organic pads next time I think as it does my head in…

Right sorry guys just found out the pads I bought were semi metallic, whatever that means but I’m still confused as the problem started with some other pads I then put some old resin ones in and still the same so I bought these semi ones…I took the bike to ride on a few months ago when the back one was screaming and a leaky calliper was the conclusion but the front was fine…so the back one is now fine and the front has come out in sympathy…

So I’ve tried 3 different pads two rotors the only thing that has happened is new forks couldn’t be anything in that area could it….they were installed by ride on so can’ t think why…..

I’ m out of ideas ..anyone got any old 180 rotor I could buy/ borrow to check, a non resin only pads version…

Thanks for all the advice….

Anthony

Just of note,

Genesis IO SS
New Deore brakes (comes with organics I think)
Avid G2 rotors.
Rigid on-one forks

Front and rear squeelin’ like a stuck pig.

I bought superstar organics, and exactly the same problem. Changing the mass/damping of various components doesn’t seem to affect it (vibration f=ma+cv+kx), so it needs to be stopped at source. I’ve tightened all bolts, cleaned and relubed. rotors have been sanded down and re-bedded in. Rotors is my next step too, so you’re not on your own!

what make of brake adaptors?

I’ve been through this. Did everything with my new 2012 SLX brakes (clean, bleed, refit, cook, IPA, new pads, scrub). In end took to LBS who rang Madison to find out that these were from a dodgy batch, Madison sent a new set out FOC. All sorted after hours of work and squealing. HTH

Bringing up old info, but may be useful to others:

Avid Bedding in Procedure

Shimano Bedding in Procedure

Shimano Brakes and Heat

I think I’m going to have a crack at re-grinding the discs back to fresh steel and removing all evidence of friction material. Followed by trying a proper bed in procedure. Theory being that the discs currently have microscopic variations in thickness causing vibrations.

It’s got nothing to do with that.

Shimano brakes blow their seals after a year or two, and spray a very fine mist of their mineral oil onto the rotors / pads. This causes the horrible squeal.

When this happens, the calipers and pads are writeoffs. Calipers because you can’t get new seals for them, so have to replace the whole caliper. Pads because when they get contaminated with mineral oil, nothing seems to work to clean them.

I tried on multiple occasions to get rid of the squeal. I tried sanding the pads, brake cleaner, isopropyl alcohol, meths, heating in oven, heating in grill, soap and water, filing surface, replacing pads, sanding discs, cleaning discs, replacing discs, replacing pads.

Frankly, I wouldn’t touch Shimano brakes again. Did 5 years of it. Worst was both brakes totally giving in on the same ride in minus 5 degrees. Had to ‘ride’ home with no brakes. Pathetic.

Good when they are new, but you need to throw them out every year and get new ones.

On to Hope now, much better!

nikk +1 went through all of this with mine ended up replacing rear caliper which has sorted it out so far!! seems like after a short life they leak i have been pleased with them when working but will not buy again. Mate had similar with avids but found a couple of loose spokes which sorted that when fixed. Have you checked that yet? good luck I could not ride mine until sorted 😥
john

Sell them and buy Shimanos!

Oh wait, sorry, that only works for non-Shimano brakes…

So I’ve tried 3 different pads two rotors the only thing that has happened is new forks couldn’t be anything in that area could it….they were installed by ride on so can’ t think why…..

There we are. New forks = different system resonance. You need to change some aspect of the brake system to get away from the resonance. Seeing as you’ve already done same size rotors and pads, try a bigger rotor.

Shimano brakes blow their seals after a year or two, and spray a very fine mist of their mineral oil onto the rotors / pads.

FTFY

brakes blow their seals after a year or two, and spray a very fine mist of their oil onto the rotors / pads.

Standard DOT brake fluid is not oil though. FWICS, standard brake cleaner works well with clearing off DOT brake fluid. Nothing shifts Shimano oil.

And if a part needs yearly maintenance, why make them unserviceable? Total nonsense IMHO.

There we are. New forks = different system resonance.

There shouldn’t be anywhere near enough vibration to set up any large resonances. I highly doubt it is the forks at fault, when Shimano are known for this exact blown seals / howling brakes problem.

The calipers need replaced. Better yet, throw out the Shimano brakes and buy something that a) uses proper brake fluid, and b) you can replace the seals on.

I have this problem with my deore m596, bought easter 2012, worked until January and ever since have squealed terribly with no power. Have tried lots of pads, ended up with new pads and rotors at the same time, bedded in and worked for a few days couldnt believe the increase in power. Now both squeal at start of ride, though front still has power once warm, I cant even lock up the rear.
Got the lbs to shorten hoses around when this problem started and had to go back for a bleed, could there be a connection? Am I too late for warranty?
lbs also complained about me storing it upside down but im afraid looking after expensive forks wins over £40 brakes…

rsl1 – that is classic Shimano brake syndrome. The cold in January has knackered the caliper seals. You need replacement calipers, or better yet, throw the whole Shimano brake system out, and buy some Hopes.

cheers, I will see how far I can get with warranty claims as I am low on funds. Put up with the brakes and use spare cash to ride for now!