Hi all, My 2008 prius (about 187k miles) is, at times, making a grinding noise up front - I believe the left front. Today was a classic example: I left the house earlier and there was a grinding noise up front. It sounded worse when I made left turns. I parked for a couple of hours, then on the drive home the grinding noise was completely gone and the car drove as smooth as glass. I was concerned since the noise sounded serious - like a bearing or brakes grinding etc. My brake pads and rotors are both about 5 month old or so. And this happens off-and-on. Will be perfectly fine for days, then make this noise - which eventually goes away. Anybody have any ideas? Thanks, Rob
Sounds like the classic rotor rust issue to me. If the brakes aren’t used frequently, they develop a layer of rust that has to be “burned off”. You can always put your Prius in neutral from time to time and stop using the friction brakes and not regen braking . That’ll lessen the number of times you hear the noise.
I've also had the inner wheel well liner come loose and rub a tire at certain speeds or wheel positions. Sounds just like a loud grinding noise.
thanks for the replies. If it is the rotors shouldn't it happen all the time? I've had rusted rotors before - which is why these are so new. Plus I drive it almost every day so shouldn't that keep rust away? I will check the liner tomorrow. Rob
They get surface rust on them. Then when it gets removed, it makes noise. Search around here and you’ll find many examples of this behavior asked about and commented on. Good luck and keep us posted .
A local garage did the brakes and rotors. Also - any issue with putting it in neutral while driving? I don't want to accidentally put it in reverse.
Noises in the suspension and brakes should be inspected properly. Most places do it for free so that they can potentially earn your business
no issue putting it in neutral under 30 mph. doesn't take much braking to get the rust off. mine comes off just backing out of the driveway, unless its been sitting a long time
Also, it's impossible to put it in reverse above 7 mph. It will beep and put it in neutral if you try. I have.
update - I drove this morning for about 1.5 hours (I drive for lyft on the side). Absolutely no noise whatsoever. Steering is smooth, braking is noiseless with no vibration etc. Haven't tried the "neutral brake" thing yet - but will. Weird how I had a sound that was so bad I thought I would have to put the car into the shop the next morning, and then it just disappears... Rob
I live in overtly "damp most of the year" London, where an overnight deluge can turn the brake discs rusty - overnight. Even more so if "The Spaceship" is not used over the weekend. The result of such rust formations on the discs is repetitive grinding noises which will sometimes manifest themselves as soon as you start moving. As I live at the top of a hill (I've fondly dubbed "Cloudbase"), I tend to do emergency braking as I roll down the hill, in an attempt to dislodge the thinly coated rust formations. Occasionally, even that doesn't work and I'm left with a repetitive "squeak.... squeak..... squeak..." noise which will usually resolve itself after a mile or two of continuous driving. I note there is less of this during the brief hot London summers, and more of this phenomenon as it gets colder and arguably damper. NUU_M3 ?
drove again today for about 2 hours. No noises, no problems... Think it was just some rust. Thanks again, Rob
If your Prius lives outside it will quickly get rotor rust. Most cars do but the Prius really makes racket. The crunching screeching will happen the first time in the am when you go the first brake. If car is garaged it will be fine. It’s a good thing to keep an eye on the front brake rotors. Once in a while look through the slots in the front mag wheel and look at the rotor surface. Should look like extremely smooth steel. No pits no circular scratch lines. No rust. Just smooth surface.
update - I did the neutral/brake thing but the issue was still there - grinding noises every once in a while. The other morning it was so bad that I took it into the shop, and it was the front left bearing. I got it repaired - about $300 - but when the mechanic tested it the ABS VCS light came on. He replaced the ABS sensor with a new one and the light went away and I took the car home. Later that day - after the shop closed for the weekend - the ABS light started to come on every once and a while. Random. I did a quick google and it seems to be an issue that has come up before, so I will create a new thread. I hope this post helps someone in the future, Rob
