inconsistent brake squeaking, only happens with light brake

[Tcoat]

Originally Posted by humfrz

I find that if I don't write things down, I forget, then they didn't exist -

I don't have to write anything down. I have a wife. She WILL remind me.

[humfrz]

Originally Posted by Tcoat

I don't have to write anything down. I have a wife. She WILL remind me.

.....an oldie -

[szjalo]

sorry for the late reply, pads are thin but not to a point to touch the indicator pin. I will replace pads as well as the hardware.

doubt the noise is from the pad being too thin, because that would be a continuous noise instead of occasional, right? The fact that my noise only come up under certain circumstance seem to imply something else?

I also notice noise will be completely gone for couple days after any rain. then came back after couple dry days. This reminds me my old bike, making rattle sound everywhere until it rains and noise goes away but came back after few dry days.

[jflogerzi]

Without knowing pad material and rotor history it's hard to know. These are stock breaks or PP brembos

Sent from my GM1915 using Tapatalk

[Ultramaroon]

Originally Posted by szjalo

sorry for the late reply, pads are thin but not to a point to touch the indicator pin. I will replace pads as well as the hardware.

doubt the noise is from the pad being too thin, because that would be a continuous noise instead of occasional, right? The fact that my noise only come up under certain circumstance seem to imply something else?

I also notice noise will be completely gone for couple days after any rain. then came back after couple dry days. This reminds me my old bike, making rattle sound everywhere until it rains and noise goes away but came back after few dry days.

When the pads are thin they lose the damping coefficient of the pad material. Track pads sing because the compound is much harder than street compound. At elevated temperature, when a street compound would already be smearing, track compound softens just enough to achieve maximum effectiveness.

After rain, the tiny voids in the material fill with rust just enough to damp the vibration. Then as they are used, that dust clears and "riiiiiing!" Your old worn drive chain did the same thing.

Also, because they are thin, the brake pots (pistons) are extended that much further from the cylinders. That also contributes to the ringing.

[churchx]

Well, imho biggest source of noise (reasoning by track pads noise going down on track) for track pads is that their working temp range is too high to be reached during normal braking driving on public roads .. so bedded layer quickly wears down, resulting in squeal. Track crowd usually takes extra care to keep brakes working properly, frequently switch pads, so wear level rarely comes as surprise and thus i don't think that pad high wear is common noise culprit.

For street pads squeal might be due them worn too much, and as many of them have "brake wear indicator" in form of embedded metal plate that scratches disk with noise once high wear level reached. People only daily driving their cars often care way less about regular diagnostics and also often try to use parts (including pads) past reasonable wear rates ..

As to OP, if wear level is certain to not be issue (has he checked pad thickness?), i'd think first of trying to rebed brakes with repeated hard stopping and see if that doesn't fix noise issue. "should still have some life left" sounds more like guesswork, not measurement.

[szjalo]

update: I took the pads down just to be sure that I was right about their remaining life. Turns out they aren't that thin either. I think I could have driven another 10k miles on these pads, especially I am doing 95% hwy.

Still couldn't tell where the noise is from. Many of you commented that the pads are too thin, which turned out to be not the case. I still do not think thin pads (rotor/pin contact) can result in an *inconsistent* noise.

My best bet is loosen/ dirty hardware. my old brake clips are not loosen but they sure have baked on brake dusts.

Since I ordered new pads and hardware, I replaced the old pads and clips anyway, also lubed the pins. So far so good. but the noise problem was its inconsistency. I will see if the noise pops back at some point.

[Jdmjunkie]

Lube the slides on the caliper and lube the back of the pad. See what happens.

[Ultramaroon]

Originally Posted by szjalo

I think I could have driven another 10k miles on these pads, especially I am doing 95% hwy.

Easily. If you have calipers of the measuring type, you can inspect them for uneven wear. Might even see it. Not necessarily horrible as long as the pins and guides are in good shape but I would not continue using them. I'm not big on the damping grease but the service manual does call for it.

New rotors are cheap enough to replace along with fresh pads. That gets your pots fully sunken back into the calipers and gives the new pads a nice start.