I like Shimano brakes but

rowdyflat

rowdyflat

chez le médecin
About 1/3 of my Shimano brakes squeal what ever I do.
Have looked for oil leaks in the caliper.
Have sanded the glazing off the pads.
I have not cooked the pads or sanded the rotors I have tried cleaning 1 of them with alcohol .
Does anyone have a theory ?
Never have the problem with Formula DOT brakes doesnt DOT squeal.
Is it the mineral oil is somehow on the rotors ?
Is it possible the pads are slightly poorly aligned in some calipers ?
 
H

Halo1

Likes Bikes and Dirt
Mine Squeal after they get wet for a bit then the are fine after a few sections of heaven braking.
Have you tried mixing up pads and new rotors?
Could there be some kind of vibration somewhere.
I hate dealing with dot fluid so am a mineral oil fan boy now.
 
Stredda

Stredda

Runs naked through virgin scrub
rowdyflat said:
About 1/3 of my Shimano brakes squeal what ever I do.
Have looked for oil leaks in the caliper.
Have sanded the glazing off the pads.
I have not cooked the pads or sanded the rotors I have tried cleaning 1 of them with alcohol .
Does anyone have a theory ?
Never have the problem with Formula DOT brakes doesnt DOT squeal.
Is it the mineral oil is somehow on the rotors ?
Is it possible the pads are slightly poorly aligned in some calipers ?
Click to expand...
I've never actually had a bike with Shimano brakes. Not by choice, they just happen to all have had some kind of SRAM brakes.
All of my bikes have squealed in the wet to some degree. I'm assuming your brakes are squealing all the time?
They shouldn't squeal all the time, but some just seem to be worse than others. You could try using sandpaper to rough up the pads and the disk then bed them in with some hard braking. Have you tried new pads and are you using organic or metal type pads?
 
Dozer

Dozer

Heavy machinery.
Staff member
rowdyflat said:
Have sanded the glazing off the pads.
I have not cooked the pads or sanded the rotors I have tried cleaning 1 of them with alcohol .
Does anyone have a theory ?
Click to expand...
I'm an expert on brakes. I've gained this qualification because I've fucked & fixed that many of them. ;)

-Never sand your pads. Its just adding / spreading more contaminants.
-Never try to clean them with anything other than water.
-95.3% of the time, if you've got anything other than air on your pads, they're as food as fucked. You can attempt to remove the contaminant with a heat gun but it will generate that glazed squeal effect. First thing; clean your rotors with soapy water. I've found any kind of brake cleaner or whizbang super dooper brake fixer liquid just makes it worse. To do this, take the pads out and sit them pad material side up on a surface that won't catch fire. Get a heat gun and get the pad surface nearly glowing. You'll see the odd puff of smoke come off the pad, thats the nasty stuff coming out. Let them cool then once you can touch them chuck them back in our caliper. The next part is important, don't slack off on it. The brakes will feel slow to respond and make some shit noises but this is the bedding in procedure that I've followed for 40 years (give or take....). Ride your bike up and down the street getting the pads and rotors pretty hot. Try not to pull up to a hard stop but slow down at the spot that you've got a spray bottle of clean water. Spray the pads through the caliper and the rotors. This cools the material on each surface making it bind a little quicker. I do this process until the pads start biting and the squeal stops. That can be 15 times, who knows. If they keep munching arse and won't come good then yep............they're fucked.
 
DougalStrachan

DougalStrachan

Likes Dirt
You can try the Talcum powder trick as well, give the rotor a dusting, run the brakes a couple of times like you're bedding them in and rinse off with a hose. I have a lovely packet of lavender scented talcum powder that's been sitting in my shed for years, it very rare I actually have to do this but seems to work (More often than not I've contaminated the pads with oil etc 'cos I'm a ham fisted idiot so talc wont work)
 
Cardy George

Cardy George

Piercing rural members since 1981
A different brand of rotor might help too.

Never had an issue with the Formula rotors in running now.
 
Plankosaurus

Plankosaurus

Spongeplank Dalepantski
i've had so, soooo many different levels of squeal and it can almost always be rectified (at least temporarily, if you have a fluid leak it'll coincidentally come back at the exact rate of the leak). my process differs from dozers, partly because i have full faith in the wonders of isopropyl alcohol, and partly because i'm terrible at judging the cooldown rate of my pads.

remove pads
clean rotors thoroughly with ISO and clean rag
scuff pads lightly on concrete or sandpaper
cook pads with a torch or stove
let pads cool down
burn fingers on pads because you didn't let them cool down enough
let them cool down some more
re-install and adjust correctly cooled pads
tear arse down the street, yell your favorite warcry, and hit the anchors
repeat a few times till you skid or go over the bars

should now have brakes that work and dont squeal. cooking can be a bit tricky with organics because its hard to tell when you've cooked enough, most metallics tend to be happy to just have the shit cooked out of them. they'll brake like garbage the first couple of times too, they need that new coating of pad material on the rotors before they'll work properly. You can also avoid all that cooking and burning of fingers by installing new pads, make sure to clean the rotors and bed in still though, otherwise you're likely just putting the same problem right back into your new pads.
(but realistically, who's got new pad money in this modern economy??)
 
Chriso_29er

Chriso_29er

Likes Bikes and Dirt
I'm with @Dozer , if the pads are proper contaminated with oil it's bin time.
I've been able to get temporary relieve by burning the pads, one or 2 rides. But then if the bike sat for a bit it must have seeped out from deep in the pad and the whole thing started again. New pads and nice cleaned discs and the issue has never returned.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
I have had success with the moorey method of baking in a BBQ for half an hour or so. I prefer metal pads and these seem better.
 
Freediver

Freediver

I can go full Karen
Chriso_29er said:
I'm with @Dozer , if the pads are proper contaminated with oil it's bin time.
I've been able to get temporary relieve by burning the pads, one or 2 rides. But then if the bike sat for a bit it must have seeped out from deep in the pad and the whole thing started again. New pads and nice cleaned discs and the issue has never returned.
Click to expand...
If there's anything left to seep out you didn't get them hot enough.
 
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