Grinding noise when braking - Only 42000 km on 2004 Prius

[Eug]

I've had squeals before (last year, not recently), but today when I was braking I had a low frequency noise almost like a cross between grinding and rumbling.

Anyone hear this before? I'll take my car in tomorrow, but AFAIK, worn brake pads shouldn't sound like this. I see in the manual though there is some brake warning noise when the pads are worn. Is that it?

At 42000 km I wouldn't have expected it was my brake pads, at least on a Prius (2004).

[seasalsa]

<div class='quotetop'>QUOTE(Eug @ Jan 21 2007, 12:21 PM) [snapback]378756[/snapback]</div>

I've had squeals before (last year, not recently), but today when I was braking I had a low frequency noise almost like a cross between grinding and rumbling.

Anyone hear this before? I'll take my car in tomorrow, but AFAIK, worn brake pads shouldn't sound like this. I see in the manual though there is some brake warning noise when the pads are worn. Is that it?

At 42000 km I wouldn't have expected it was my brake pads, at least on a Prius (2004).
[/b]

You probably picked up a rock and that is what is making the noise. Most Pruis show only mimimal pad wear at 42,000. I had a similar occurence with my previous car, sounded really bad but went away on the way to the shop.

[Tideland Prius]

<div class='quotetop'>QUOTE(Eug @ Jan 21 2007, 12:21 PM) [snapback]378756[/snapback]</div>

I've had squeals before (last year, not recently), but today when I was braking I had a low frequency noise almost like a cross between grinding and rumbling.

Anyone hear this before? I'll take my car in tomorrow, but AFAIK, worn brake pads shouldn't sound like this. I see in the manual though there is some brake warning noise when the pads are worn. Is that it?

At 42000 km I wouldn't have expected it was my brake pads, at least on a Prius (2004).
[/b]

wow, you have the same mileage as me at 42,000kms!

Hmm, I've heard some squeaks before from what seemed like is emanating from the left front wheel but the techs couldn't find anything.

I have had my front brakes squeak before but I just assumed it's because it's cold and I haven't used them in a while.

Did you try braking in neutral to clean the discs?

[Eug]

Thanks.

I didn't try the neutral braking thing. What does that do?

Anyways, I went in and they just suggested a general brake service to clean off the rust and stuff. (The pads were OK at 70%.) So I did and there is no more noise.

[jdenenberg]

<div class='quotetop'>QUOTE(Eug @ Jan 23 2007, 08:09 AM) [snapback]379443[/snapback]</div>

Thanks.

I didn't try the neutral braking thing. What does that do?

Anyways, I went in and they just suggested a general brake service to clean off the rust and stuff. (The pads were OK at 70%.) So I did and there is no more noise.
[/b]

Putting your Prius in neutral prevents regenerative braking and forces the use of the friction brakes. This will quickly clean off any dirt or rust accumulation on the disks (front) or drums (rear).

The other issue is the sliding pins on the front calipers (they allow the calipers to stay centered). If they get stuck, you will wear the inside-outside pads unevenly which shortens pad life (pads commonly last more than 100,000 miles on a Prius, mine are just barely worn at 78,000 miles). The caliper sliding pins can easily be cleaned and lubricated by anyone familiar with disk brakes.

JeffD

[Eug]

<div class='quotetop'>QUOTE(jdenenberg @ Jan 23 2007, 08:54 AM) [snapback]379445[/snapback]</div>

Putting your Prius in neutral prevents regenerative braking and forces the use of the friction brakes. This will quickly clean off any dirt or rust accumulation on the disks (front) or drums (rear).

The other issue is the sliding pins on the front calipers (they allow the calipers to stay centered). If they get stuck, you will wear the inside-outside pads unevenly which shortens pad life (pads commonly last more than 100,000 miles on a Prius, mine are just barely worn at 78,000 miles). The caliper sliding pins can easily be cleaned and lubricated by anyone familiar with disk brakes.

JeffD
[/b]

Well, what I did do was go faster and hit the brakes a few times. It just made that disconcerting noise again so I stopped doing that.

P.S. Is my 30% (70% left) more than usual? I do note I jackrabbit a bit more than other people. Not good for gas mileage either.

[SomervillePrius]

I don't know if 70% left of the pads at 42000 miles is good or bad (I think it's slightly below average), but I felt I needed to comment on jack rabbiting. On my old car (a 96 Maxima) I had to change break pads frequently due to my driving style. It was a game to be "fast" then. On my prius the new (obsessive) game is to get great MPG (keeping climiate control of when possible, installing pipe isolation in the front grill, driving back roads to work & pulsing and gliding as much as possible). I'm sure it will help my service costs in the end

[Eug]

<div class='quotetop'>QUOTE(SomervillePrius @ Jan 23 2007, 10:58 AM) [snapback]379499[/snapback]</div>

I don't know if 70% left of the pads at 42000 miles is good or bad (I think it's slightly below average), but I felt I needed to comment on jack rabbiting. On my old car (a 96 Maxima) I had to change break pads frequently due to my driving style. It was a game to be "fast" then. On my prius the new (obsessive) game is to get great MPG (keeping climiate control of when possible, installing pipe isolation in the front grill, driving back roads to work & pulsing and gliding as much as possible). I'm sure it will help my service costs in the end
[/b]

Actually it's 42000 km, so I guess I'm definitely below average for a Prius then. :P

The other problem is I work in a big city, live in that city's downtown, and thus drive through that city to get to work, with tons of traffic and traffic lights in between. So, I'd say 95% of my driving is stop and start to begin with, so I guess I'm not too surprised by my worse-than-average-but-otherwise-relatively-OK brake pad wear.

Do you guys regularly do this brake in neutral thing, or only when squeaking etc. shows up? Or do you just take the car in to get the brakes serviced once in a while? (We get lots of rain and some snow here, and there's tons of salt on the ground in the winter, so I can see brake rust easily being a problem with these cars.)

[hobbit]

You really don't want to just wham on the brakes in "D" to try and
clean them off, because you're not keeping *even* pressure on the
pads. Use the Neutral trick, and give it a nice steady-foot cleanoff.
Yes, the car might need this every day or two [just one or two
slowdowns, no big energy hit] especially when it's wet out.
.
_H*

[galaxee]

70% is quite low. was this measured by guess or by actual physical measurement?