[BouncingRadical]

My brakes started squeaking the other day when they where cold. Does this happen to anyone else? And is it remediable?

[Sangria7]

Mine does it all the time only on slow braking

[Munch]

OH NO..not the break squeaking… lol. Sorry the one time I get to get away from mechanical stuff and now i find it on here… just kidding. However:

1) Disc brakes on most bikes will have a tendency to squeak and squeels for several reasons. The disc is a very thin piece of metal with very little harmonic dissipation. The pad depending on the maker is a bonded material with various particles in it to help with friction, wether it be semi metallic…mixture of soft metals like brass in it. ceramic…. very hard material, or “organic” which has some cork in it and various other stuff. Mash a hard friction against a thin plate and alot of vibration is going to happen, with decent engineering you can mask this with a counter harmonic of the same frequency to cancel the sound. Less then stellar engineering will give you the same effect of rubbing your finger over the top of a balloon. If the pads are not isolated well enough in the caliper or the disk is not of the proper thickness it will allow for vibration, which causes the audible squeal or squeak.

2) The disc or rotor is a piece of machined metal, untreated and very susceptible to moisture. In high humidity areas and/or prolonged sitting surface rust will form and cause the extra vibration aka: Squeal until used numerous times to get to a clean flat surface.

3) If you are prone to “riding your brake” you can cause a mirror like finish on your pads thus creating the effect of rubbing two pieces of glass together.

4) Above I mentioned pad materials…semi metallic and ceramics are prone to squeaks do to the hard materials used. Ceramic is a very hard material and for obvious reason does not have the ability to absorb the vibrations, semi metallic has the “soft” metal particles in the pad which has no guarantees of how it sets when the pad is cured out at manufacturing… some pieces can become small squeal tabs until worn through. Oh yea, not to mention the road debris like sand and the current season, salt, can get between the pad and disc causing more availability for the vibration to occur.

Final Note: This is not just for motorcycles but also for automobiles of any type. If you hear a squeal do not panic just do your pre ride check as you should and judge your wear, look the disc over for gouges to to indicate debris. If pads are normal or new and no gouges check for excessive play between the pad and disc at no pressure. If there is excessive up and down play with the pad it will likely cause a vibration aka: Squeal. If none and depending on use, age, and repair history check with your mechanic to make sure the Disc is at the appropriate thickness.

[BouncingRadical]

Thanks man, I believe its the 2nd reason as it started on a really misty day and continued for a while. But like a bad tooth once you go to the dentist it stops hurting and it stopped yesterday. The film of rust must have been worked out. Thanks a ton munch, sorry to bring up mechanical issues heh.

[Munch]

No worries… glad I can help.
If I know an answer I am more then happy to share what I know.

[Sangria7]

Munch knows something?

[Munch]

shhhhhhhhhh….don’t tell anyone… then they will expect it all the time…

[Munch]

possible… would take it to a mechanic to make sure. unless the cable is just really screwed somewhere down the line the only place left is the clutch assembly. It may also be just a hydraulic thing. Lack of pressure….or fluid….or both. In which case… mechanic would still be a good idea.
There again…. it’s an HD…. lol…might just be the nature of the beast.

[texreb]

After my truck has been sitting for a couple of days (particularly when very humid) when starting my brakes will “grab” with a light touch. After the sending you through the windshield once it does not do it again.
I have been told that this is because the rotors get surface rust and this is normal (seems reasonable to me). When I told this to someone who was riding with me said he had never heard of it and thought I was just trying to get out of doing a brake job.
Rotors feel pretty straight still (no pulsating at low speeds while braking), does not have the feel of sticky calipers (typically a pull to the right (just because that seems to be the one that goes out first b/c of more temp change)).
Does the rusting sound legitimate, or like a serious problem?

[Munch]

“grabbing”….hmmm my first question is do you have rear drum brakes?

[SantaCruzRider]

Wet clutch can start getting sticky when the oil is worn. First fix might be just to change the oil and see if it helps. Beyond that, it could be everything from clutch spring getting too tight to warped friction plates (usually only happens with someone who is riding the clutch stunting) –doesn’t sound like you.

[Loki]

Wow thanks, i was about to ask why my breaks speaked. Its the first reason. Cant stop it and i dont know if its stopped since being put up (havnt noticed it). Also took the whole break apart and looked it over, so did the bike mech. Both of us found nothing wrong.

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