Took the Prius up to Mammoth Mountain this past weekend. Noted some interesting things about the car at high altitude which I'll post in due time. But something weird started happening, and that's the topic of this post. A weird chirping noise started coming from my right front wheel. It started happening one night when it was about 30 degrees out, so at first I thought it was temperature-related. Whenever I pressed the brake pedal a short "chirp" would come from somewhere by the right front wheel. The noise does sound hydraulic in nature - it's similar to the "singing" a spigot might make right before you close it. But it's very regular in pitch and duration no matter how quickly or slowly I depress the brake pedal, or whether the car is moving or not. At some point in the pedal's travel the chirp would happen. The brakes otherwise seem to be behaving as normal, and the chirp stayed with me all weekend. I drove home today, and the chirp is still there, although it's happening less frequently. When it first started happening I could be in park and repeatedly press the brake pedal and the car would go "chirp! chirp! chirp!" Now that I'm home, it chirps only occasionally. This probably means, among other things, it's not temperature or altitude-related. As it happens I'm due for my first oil change anyway, so I'll have the dealer take a look at it. Just curious whether anyone else here has heard this noise before.
I've had the noise 3 or 4 times, over the past two months, always upon the first breaking after starting up on a cool moist morning. I attribute it to a slight bit of rust accumulating overnight. It seems to "burn off" after the first brake application. I'd be interrested if you found out anything else.
<div class='quotetop'>QUOTE(GKarschnick\";p=\"82511)</div> Well, that would not explain why there's a noise when the car's not even moving. But here's the latest - I washed the Prius this morning, and I blasted some high pressure water behind the right front wheel, and the chirp seems to have gone away. I guess tonight, when everything's had a chance to dry, I'll see if it comes back.
One alternative theory is that you had a slipping belt (the ICE is not beltless) causing the chirp. The cold weather made it hard so it slipped. Spraying water got some gunk off the belt (which is on the right side of the engine compartment), or otherwise changed the friction properties, and it stopped slipping, making the noise go away. If it is brakes, then perhaps a slip pin got some light rust on it, and your water spraying changed that rust enough that the noise changed or went away. Or maybe Tweety will never be heard from again. He tawt he saw a puddycat, but it was a Prius.
Re: Chirping noise from brake pedal Ok. CarMyne has gone to Lake Tahoe three times and each time the morning after I arrived there is a short duration chirping noise whenever I press the brake pedal. Usually just after touching the pedal. The chirp continues each time I press the pedal even though I would drive down to Carson City and back up to Tahoe and then home to Menlo Park. After one night at lower altitude (higher temperature?) the chirp goes away. Anyway, I've made other long trips and not had the chirp occur so I attribute it to either low temperature or high altitude. I remembered this thread so thought I would see if anyone has further suggestions on what might be causing it. It is not like a mechanical chirp but more hydraulic like Hatfield describes. However, to my ear, it seems to be coming from under the dash area. Also, it does not continue after the short initial chirp even though the brake pedal continue to be in the depressed position. Any ideas?
I will but I believe that with regenerative braking, the friction brakes would probably not be engaged immediately after lightly pressing the pedal. My impression is that it is more likely an acutator or control component but I could easily be wrong. Thanks for the reply.
I also have a newly discovered chirping noise in my r) fron brake. Just had both pads and r) rotor replaced 10/15 out of state. Drove home aprox. 350 miles with no problems ( or sounds), but this morning it "chirped all the way to work!" I am a lady that is married to a disabled "not a car guy" fellow; trying to educated myself about this car. It is a 2006 with 122,000 miles on it - came with NO maintenence records - trying to do whatever people advise me to do to take care of it. Any advice?
There was a TSB on the brake chirp in 2004-2007 Prii. The brake system is identical in the 2010 so it likely to be the same cause. Air bubbles in the hydraulic system passing through small orifices cause the chirp. It is usually cleared by bleeding the brakes, but if air in the hydraulic system is due to leaks in the "Brake Actuator" assembly, this expensive part needs to be replaced. http://priuschat.com/forums/attachm...sb-br001-07-brake-actuator-noise-br001t07.pdf JeffD
