Strange creaking noise from brakes

First, make sure there is no rust on the discs, by braking to a stop while in neutral (which disables the regen). Do this on some quiet road or lot, from a moderate speed (<60km/h). That forces the friction brakes to clean the discs and will hopefully make them silent again.

The whining sound which varies when turning might be a wheel bearing gone bad. Something that happens to many a Prius, although your mileage is a bit low for that.

 

Um, bearings that are going bad won't make noise only when turning left. If the bearings had gotten to that point, then there would have been other indications. You can do a couple of things to test for bearing issues: raise the front and grab the wheel at opposite sides and try to shake it - if there is any play or movement, then its a bearing issue and needs to be replaced. Also, you spin the wheel while grabbing the spring - if there was an issue, you would feel it through the spring. Since you didn't specify which side the sound was on and that you only heard it while turning, my guess would be a power steering issue. That is where you should be looking.

As far as the brakes are concerned, your assumption seems correct since you stated there is no noise when the brakes are in use. I wouldn't worry about - most likely its just the pads moving along the pins. If it concerns you that much, then remove the pins and give them a good sanding to remove any buildup or whatever.

 

There are plenty of posts about bad wheel bearings here, with similar whining sounds reported. A specific diagnostic for this is to listen while turning sharply left or right. Do this in a safe place at reasonable speed. This will load the bearings on one side or the other. If the sound changes while doing this, it is safe to consider the possibility of the bearing on the side which makes the whining sound is going bad. Further investigation is of course wise.

 

If you have a way to make a video with sound, post it on you tube and then link the video here on Prius Chat. Maybe with the group "hearing" what you are talking about will help to narrow it down.

 

Once you get the video uploaded on youtube, copy and paste the URL of the video into a post in this string. Everyone will be able to see it unless you have copyrights set up on your account.

I think that might help. Brake sounds are pretty unique in my opinion. Be a good idea if you can figure out if the sound is coming from the front or the back also.

 

could it be the vacuum pump ?

i assume the prius has an electric vacuum pump for the brakes when the ICE is not running.
maybe it this pump making noise ?

only a guess on my part though.

Jason

 

True. The early signs of a bad wheel bearing are associated with noise - some with a "wuh wuh" type of sound and some with a whine. But the noise wouldn't just appear when turning. Be sure to check the wheel bearing on the opposite side of the noise. As stated in my previous post, there are other tests you can do than just turning - but by the time it gets to where there is play in the bearings, they will be really bad. Same experience on my Tacoma, the bearings went bad at the differential side instead of the spindle side.

Have you checked:
CV joint (this could be very possible)
brake shield (unlikely unless for some reason it rubs only when turning)
Lower control arm

There are many things that can be the cause of it - I wouldn't rule out bearings but that appears to not be the cuplrit given what you are describing.

 

The Prius has an electric pressure pump called the brake actuator, not a vacuum pump as in a standard car. It can make odd noises, and hopefully the OP's recording will show if this is the suspect or not.

 

thanks for the info.

my reasoning behind suspecting the pump, is the OP said it makes the noise when stationary too.
when stationary, there would be zero rubbing from pads, or bearings to make noise.

 

See the TSB embedded in the following string:
TSB BR001-07 Brake actuator noise | PriusChat

 

Raise up that corner of the car, and remove the wheel, so that you can observe the caliper and disc as the brake pedal is depressed by a helper. Maybe that will help you to identify the source of the noise as the caliper or some other part.

The creaking noise does not sound like the noise produced by the brake actuator, the latter produces a barking sound.

 

Could be.

What is the thickness of the brake pads? Is the wear uneven?

 

I think you should start by replacing the front disc pads on both front wheels, then see if the noise persists.

Maybe the noise is caused by the caliper piston sticking out near the end of its travel range, and wobbling around.

Regarding pushing the piston back into the caliper, I hope you are using a C-clamp, as that would make the task very easy. Also, watch the brake fluid level in the reservoir, and suck some of the fluid out if needed to ensure the fluid doesn't overflow.