disc brake squeal

[eddief]

i am relatively new to disc brakes, these on my 2019 Roubaix, these being Ultegra. the pads were replaced by LBS about 300 miles ago and they were perfectly fine for all that time till now. high end shop so i think the pads were bedded properly. they don't make noise while braking and still having a few rpms, but just before the final stop and as i release the levers at the stop, they squeal like crazy.

i cleaned rotors with alcohol and sanded the front pads but no improvement. should i assume the pads somehow got contaminated and are not fixable?

[Spdntrxi]

last time my pads where contaminated.. I took a propane blow touch to it and cleaned with Iso. alcohol. it worked.

[eddief]

and which part did you apply alcohol to?

Originally Posted by Spdntrxi

last time my pads where contaminated.. I took a propane blow touch to it and cleaned with Iso. alcohol. it worked.

[fogrider]

after washing with alcohol, soak/wash with soap and water.

[eddief]

clarify.

QUOTE=fogrider;2768959]after washing with alcohol, soak/wash with soap and water.[/QUOTE]

[merlinmurph]

Generally, that's because the pads got contaminated. Did you ride in the rain lately, or something similar to contaminate the pads?

People have various amounts of success cleaning the pads. It's worth a shot with new pads.

Good luck.

[MikeD]

Do you have the L02A pads? My front squealed under heavy braking. I replaced them with the L03A pads, which are the new replacement for the L02A and they are supposed to last 40% longer and I think they are silent now. I also bought a pair of Swiss Stop Exotherm2 pads that I haven't tried yet.

[eddief]

1. remove rotors, sand lightly with 240 grit, clean with finger nail polish remover.
2. remove pads, scrub with toothbrush and finger nail polish remover.
3. after they're dry, put 240 grit on work table, turn pads face down, and sand lightly until original bronze color takes the place of the darkened material.
4. blow off dust, make sure you don't touch the pads with your fingers.
5. use qtip and rag to clean outside surface of pistons.
6. reinstall pads.
7. do bed in process of your choice. me, ride like crazy in 10 short bursts and apply brakes hard each time.

as of now without lengthy test ride, brakes seem back to working how they should. time will tell.

[SoCalSteve]

Originally Posted by eddief

i am relatively new to disc brakes, these on my 2019 Roubaix, these being Ultegra. the pads were replaced by LBS about 300 miles ago and they were perfectly fine for all that time till now. high end shop so i think the pads were bedded properly. they don't make noise while braking and still having a few rpms, but just before the final stop and as i release the levers at the stop, they squeal like crazy.

i cleaned rotors with alcohol and sanded the front pads but no improvement. should i assume the pads somehow got contaminated and are not fixable?

Happened to me like that and I just replaced the pads and rotors. Silent....well, when there is moisture on them they squeal until I scrub off the moisture, then silent again.

[R3awak3n]

to me its just a free bike bell... goes well with the loud rear hub

[eddief]

just in case you try this approach. i got on the bike this morning and hit the front brake at the start of my ride. squeal. cuss. hmm. maybe a few more bed in maneuvers would fix. so i sped up applied the brakes hard while pedaling for a few hundred yards a few times. tried stopping normally again and squeal gone both front and rear for 25 miles.

[unterhausen]

Back when they were running group rides, I would just ride around the parking lot making the brakes squeal until the lbs owner said to bring the bike in.