My disc brake pads seem to have plenty of material left but they somehow got contaminated and squeaky. I tried sandpaper on the pads to freshen the surface, and cleaned the rotors which helped for a while. The rotors are still stained though. I can’t stop the squeal in the last ~20% of lever throw.…

Firstly squealing is not a sign of contamination, a reduction in braking force or a complete inability to stop is. My brakes always squeal when they are wet. its just what disc brakes do. A few hard stops when they are dry and the squealing goes away. If you can stop safely with your current rotor …

I’ve used this method (using a torch) and it worked. Bicycle Maintenance: How To De-Contaminate Disc Brake Pads (youtube.com) If installing new pads, I wouldn’t sand the rotors. Just give your new pads a good break-in period.

[image] Follow the directions and it will stop your squeal….however, it is not a permanent solution and you’ll need to reapply after awhile. But it definitely works. Just make sure you follow the directions….if you just slap it on and start riding, you…

[image] JonGreengrass: Firstly squealing is not a sign of contamination, a reduction in braking force or a complete inability to stop is. The rotors have lots of dark streaks and the surface of the pads looked gunked up (is that the technical term? :rofl:) before I sanded them the first time.…

I have had success sanding rotors to resurface, it helps get all of the bedded pad material off. I think this is important if you’re switching pad compounds or you’ve been dealing with contamination. Some tips: Wear latex / rubber gloves to keep all oils / contamination off the rotors. Clean v…

imo, id use the flatest hard surface to sand against. “Lapping” I’d worry freeballing it would make the pad/rotr not flat

“bedding in” disc brakes smears material from the pads onto the rotors and the pad material across the pads, this is probably what you’re seeing. The alignment I’m talking about is too small to be seen, follow the process I mentioned for replacing wheels and the squealing may resolve itself.

I’ve had this exact problem, and have personally had great luck cleaning my rotors thoroughly with rubbing alcohol and a clean fabric rag (don’t use paper towel, it’ll fall apart).

Over the years I’ve had about half a dozen shimano hydro road and gravel bikes sharing about a dozen wheelsets between them. I think I’ve dealt with most issues now and have come to the following conclusions: Most glazing, bedding in, and even relatively significant contamination issues can be de…

I didn’t see any mention of pad material. In my experience, metallic pads are gonna squeal under some conditions (especially when wet) regardless of what you do. If the noise bothers you, switch to resin pads. They are much less prone to squealing (but wear out much faster and don’t quite have t…

Rotors OK to clean and use with new pads?

Equipment

bmcd December 30, 2023, 8:40pm 13

This is the way.

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Disc Brakes and Pads that *DON'T* squeal?

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Rotors OK to clean and use with new pads?

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