This is a "WIERD ONE"

This happened to our 2004 around April of that year. We had been inspecting some property my wife owns in Mississippi and had stoped to make a U turn on a country gravel road. Upon starting up a terrible metal sound erupted from somewhere at the front of the vehicle. We were 15 miles from the nearest town and not haveing the Prius more than a few months, thought the worst. Tried driving it again, but, the noise was so bad that we pulled over and called Toyota Road Side Assistance. They sent a flatbed tow truck and hauled it to the nearest dearler 35 miles away. The Toyota dealer called about an hour after receiving the vehicle telling us that a small rock (pea size) had lodged between the disk rotor and dust shield. The dealer indicated that they have had other incidents happen from rocks and disk brakes, but, was a first for a Prius.

 

As a follow up note, I had a wheel bearing fail and it definitely did not make scraping noise. It make what could best be described as broadband amplified road noise. Also note that the rear brakes are enclosed but the front calipers are total exposed.

 

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Aug 12 2007, 05:30 PM) [snapback]494394[/snapback]</div>

We were driving home the other night and we heard a loud sound, almost as if we were dragging a branch under the car. We stopped for a light, and when we started up again it was gone. We definitely were not dragging anything. We have not heard it since. :wacko:

 

The thin metal backing plate will act like a speaker to amplify the noise while the stone will be like a stylus on a very bad record as it drags across the brake rotor. Go backwards for a few metres to clear the stone if it happens, may or may not help. Wheel bearings rumble or growl when they fail and yes, they don't fix themselves.

The thin metal backing plate will act like a speaker to amplify the noise while the stone will be like a stylus on a very bad record as it drags across the brake rotor. Go backwards for a few metres to clear the stone if it happens, may or may not help. Wheel bearings rumble or growl when they fail and yes, they don't fix themselves.

 

Speaking as one who spends a lot of time driving on rural roads, your symptom is most probably a stone lodged against the brake rotor. Sometimes if you put the car in reverse and drive for a few meters you can flick the stone back out. If you've driven with it in there for a while, however, this will probably not work (it will stop the noise for a while only to begin again when the stone shifts position). If that's the case, get it removed by a mechanic -- it will score your brake rotor. You and your wallet don't want that.

 

<div class='quotetop'>QUOTE(samiam @ Aug 13 2007, 04:50 PM) [snapback]494924[/snapback]</div>

Meh, depends what your noise tolerance is, and also I don't know the thickness of the prius rotor. I've had numerous rocks in the rotors and have been able to throw most out by backing up immediately after lodging them.

However! On one occasion I lodged a stone and it didn't pop out when I backed up. Being in college and having more need of beer than sitting with my rotor in my lap, I left it there. What will happen is the pebble will score a groove in your rotor. That's it. Unless you have a rock big enough to slice your rotor to a smaller diameter (which wouldn't have fit there in the first place) there's no real reason to remove it. Sure there's a fractional loss in braking power because the rock does not have as good friction as your pad, and you will have to deal with the noise till it seats itself, but if you're limited to a budget (time or money) don't stress yourself out worrying how you're gonna get the money for a pebble-ectomy.

Couple this with the fact that if your mechanic decides to turn a rotor for a brake job instead of just replacing it (which is way more common these days) you're gonna have the "ectomy" or a new rotor in X amount of miles anyway.

 

<div class='quotetop'>QUOTE(Drago3000 @ Aug 16 2007, 07:37 PM) [snapback]497381[/snapback]</div>

Huh? Probably not the best advice. Problems are easier to solve when they are little. Sort of like the doctor saying: "It's just a small kidney stone, nothing bad will probably happen."

The better advice would be a way of getting it out of there without having to go to the dealer.

 

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Aug 17 2007, 05:14 PM) [snapback]498029[/snapback]</div>

Well, unless your Prius has the sedimentary rock growing package, (#11 I think?) you're problem (rock) won't get any bigger :-p

As to how to solve it, like we said, back up immediately, or if that window is already past - take off your caliper and remove the pebble. No medical degree required.

 

<div class='quotetop'>QUOTE(Drago3000 @ Aug 17 2007, 08:37 PM) [snapback]498104[/snapback]</div>

That's much better advice.