Squealing brakes

[sethschmautz]

I have a systemic problem, it seems, on most of my bikes. Most of them currently have squealing brakes. Super annoying, and I can't figure out what I'm doing wrong or whether there by is any way of fixing it.

From what I'm reading online, it seems like squealing and vibration typical come from not bedding in your brakes correctly and that it can't be fixed. Before I buy new pads and rotors for a bunch of bikes, what advice is out there?

Any sure fire ways to making sure a new set of brakes doesn't squeal or fixing those that currently do?

Seth

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[Whiteroom_Guardian]

Bedding in definitely should be done. They probably have a "glaze" on the pads/rotors from no bed and then overbraking/overheating the pads/rotors.

Pull the pads. Sand the faces of the pads with a fine sandpaper, then clean with isopropyl alcohol and a rag. Do the same thing to both faces of each rotor. Put back together. Bed. Don't use your brakes too much in the future

[mntlion]

I have also found drywall sandpaper to work well. The small holes in it allow the contaminated pad dust to fall away, leaving good/better fresh pad

Or if you have avids that is just how they are.

[stuckathuntermtn]

Clean the rotors with alcohol too.
Also, Shimanos.

[sethschmautz]

All Shimano brakes with a mixture of rotors.

I feel like I am bedding in the ways that I see online. How are you bedding?

I have the drywall scrapers and will give that a shot also.

Seth

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[poleplant]

It can be fixed, like whiteroom said sand paper and iso. Don’t be stingy on the sanding, take that whole top layer off.

Bedding process, do it in a parking lot pedal about 15 mph then slow to about 5 mph, don’t completely stop. Do this atleast 10 more never hurts. You should feel a difference in the end


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[plugboots]

Brake cleaner, (which is an aerosol and so I’m probably killing the earth, & probably is just alcohol anyway).
That and sandpaper, and alignment, and bedding are all important. Never let anything touch or even get near your brakes.

[detrusor]

Had this issue, tried everything. Finally replaced the pads (cheap) and ran a torch over the rotors after sanding and cleaning w alcohol. Boom. Quiet.

Had done everything but the torch (including new pads) multiple times without help.


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[Toddball]

I tried the torch trick on the pads and it worked really well for half a ride, then back to squeal and no power. Just going to replace pads and rotors I guess.

[detrusor]

If you don’t torch the rotors as well you’ll just recontaminate the pads....


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[toast2266]

Aside from all the bedding advice above, try a different pad compound?

Also, I've found some pad compounds squeal until they get warmed up on a ride. On flatter trails that don't have much sustained braking, they never really warm up, and therefore squeal the whole ride.

[mcski]

A little oil will stop the squeak

[Toddball]

If you don’t torch the rotors as well you’ll just recontaminate the pads....


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Yeah. Didn't think to torch the rotors at the time. Unfortunately I've sanded pads and rotors enough that there's almost nothing left of the pads, so it's time for new ones, and I really don't want to contaminate new pads with the old rotors and have to keep dealing with this.

[stuckathuntermtn]

RT86 rotors.
I'm heavier than you, probably, so I run 8" front and 7" rear and sintered metallic pads. Absolutely no squeaking. Maybe if I've just splashed through a creek, but otherwise none.
The metal pads seem to last longer, resist fade and contamination, don't get glazed, etc. Slight loss in initial bight and modulation and the fluid really heats up, which can cause reach to grow a little when they get really hot, but otherwise, it's great. Some of the cheaper rotors may not be compatible with metal pads. YMMV.

[Shu Shu]

Having the same nightmare. Brand new brakes cura 4s, installed on two season old rotors, started off ok and then squeal on the back brake only within a couple weeks. Tried the sand and braklean advice, no luck. So I got some brand new rotors did 15 or so passes of bedding slowing very gradually, and then start applying a bit more pressure and bam squeal city? At this point I can only guess the break pads are contaminated? Or do I just need to ride them on a steeper trail to heat them up as toast was suggesting. Cura 4 organic pads on Sram centerline rotor.

[sethschmautz]

I finally had success doing the following:

Starting with rotors,
Sand with med grit paper
Clean thoroughly with alcohol
Torch
Let cool

Repeat above with pads

Reinstall everything, then do a super mellow bedding:
Accelerate to a moderate walking speed
brake slowly to slow walking
Repeat about 20 times
Do one brake at a time

A park tools video showed them using ice water to create a slurry. I tried that and it initially seemed to make it worse, but I think it paid off.

I have had success on two bikes that had really bad squealing prior.

Good luck!

Seth

Edit: sorry for the weird spacing... Not sure why it's doing that.

[Shu Shu]

All torch is the only thing I haven't tried. Blow torch time it is

Thanks

[sethschmautz]

I originally bought this benzomatic solder kit for something else, but it works really well for this application. It's fairly cheap and allows you to burn off the alcohol and contaminates without getting the heat too terribly high.

Seth