Brakes making noise

Haven't had the same problem, but I have observed that the brake discs will form a thin layer of rust in the time it takes to wash the car. Next time you brake it will clean it off. The disc metal rusts almost instantly. I assume its the alloy that they're using as I have seen this on my Solara also. Never caused any permanent squeeking or noise or affected the braking since it cleans off with the first application of the brakes. I suppose if your car is parked outside in a damp climate and isn't driven for a long time the rust would be pretty heavy.

 

Keep in mind that with regerative braking, the pads don't contact the rotors until about 7 MPH. Therefore, a thin layer of rust can build up quite easily. It normally clears itself after a while. In the 5 years I owned my 04 I never had to have the brakes serviced and so far so good with my 09.

 

This is a pretty standard problem. The brakes don't get used enough to stay clean. This is covered in several other threads, but I will repeat it here: From time to time it's a good idea to force your Prius to use the friction brakes. Pick an empty stretch of road, drive up to about 40 mph, shift into N, then apply the brakes and slow down to about 20. Shift back into D and repeat this a few more times. Using the friction brakes will clean the rotors. Do it as often as necessary to keep the rotors clean.

Tom

 

Chris11, i get a similar noise (08 prius) when applying brakes when the car is at low speeds. It does sound like some metal parts are rubbing against each other. Did you get it fixed? what did you do?


Also, each time I get this noise while applying the brakes, as I release my foot of the brake pedal I feel a little jerk in the brake pedal along with a bit of the same noise.
I checked with one dealer and he couldnt reproduce it when testing the car. He said it might be the way the braking system works in prius.

Sometimes the sound is very annoying and I am taking the car to a different dealer in a few days.

 

If you haven't yet, try what Tom (qbee42) suggested earlier in this thread. It sounds like you are having similar problems that may be fixed by "polishing" the rotors with the pads.

 

I'll leave to you the question of illegal vs. not in your local area. However it is certainly possible to shift to N from D, while you are underway.

 

I had a similar intermittent noise problem with my brakes and when I took it to the workshop the mechanic found that grit had lodged between the disk and the brake shield. After a second visit he got the rest of the grit out and the noise has disappeared.

 

Could also be the common rock-in-the-rotor syndrome. Happened to me last year, went away after a day or two. I wasn't too worried after reading about it here, must be fairly common.

 

Hi All,

Many states have laws that you are not allowed to put the gears in a transmission into neutral while driving downhill. But as your not doing that when you put the Prius into neutral mode, it does not seem to be illegal by the letter of these laws. The Prius transmission always has the gears engaged even when the car is in park. Shifting the Prius transmission control does not change the position of the gears in a Prius transmission at all.

These laws are far older than the 70's. Mechanical transmissions , especially non-synchronised manual transmissions cannot be forced back into gear if the speed between the engine and drive shaft become too different. Syncros were invented in the 30's or 40's by Ferdinand Porshe, so the law is older then that, I believe. The safety aspect is without engine drag, brakes can overheat. Overheated brakes will boil the brake fluid and result in loss of force. Hot brakes could also catch the brake pads on fire, resulting in loss of braking. And hot surfaces tend to be more slick - socalled brake fade. Even in the 80's many large trucks did not have synchronised transmissions, requiring double clutching. Getting a large truck back into gear for down hill engine braking can be very difficult.

 

I have the same problem, every time i brake i hear a metal sound, like there is no brake pads. Does anyone know what this is????

And there is also a shaking in the pedal, what is that??

 

Sometimes I hear a brief squeal when we back out of the garage first time in the morning. The sound lasts only until we are at the end of the drive, about 40 feet, and frequently doesn't even last that long. We live in a humid climate, but the car always is inside at night. I lean toward the rust or dust theory.

 

If you live in a humid climate, then it's rust, not dust. Brakes rust very quickly, some more so than others. I lived on the lake shore most of my life, and the Hondas we owned would develop a heavy coating of brake rust over the weekend. Every Monday morning I would hear grinding for the first few stops.

Tom

 

Pressing the accelerator and brake pedals at the same time also activates the friction brakes without having to put the hybrid drive in neutral.

If accelerator and brakes are pressed too far, power from the engine will suddenly be reduced, so that the brakes can always override the engine. So if you try this, make sure no one is following close behind you.

Almost every time I drive in the rain, I do this shortly before I arrive, in order to prevent excessive brake rotor rust. Usually I press the brake pedal with my left foot slowly but firmly two or three times for several seconds, while controlling power with my right foot to maintain about twenty-five miles per hour. I try to brake just enough so that the rotors are warm, but not hot to the touch, after I have parked.

But I don't do this in congested areas because it could impair my reaction time if I would need to brake suddenly.

 

Yep, I'd tend toward rust. But we also are in a rural area, and the county still hasn't paved all the roads, and there are a lot of undeveloped areas. So some dust can exist in the air because of winds. My thinking on dust as a possibility is that I only hear it first thing out of the garage and only for the two or three seconds I keep the brakes on slightly as I roll back at the door; not a lot of wiggle room for the passenger mirror. I would expect rust to remain on the rotors longer than that.

 

A light coating of rust will be gone in one or two brake applications. Heavy rust is a different story.

Tom