My Brakes are Barking at Me

Ok, I officially noticed this. Mine is 05 with 33k on it. During the weekend, I had 5 passengers in my car. I came up to a stop sign, under 5mph, the brakes barked so loud that even the passengers asked what that sound was.

I also notice occasionally that when I approach stop signs with a down grade, I will hear the barking after regen cut out.

I never notice this during last year, is this something to concern about?

 

If the sound you all are describing is like an aquarium air pump, that's the accumulator pump replenishing brake fluid pressur to the accumulator. Fluid pressure is applied to the wheels from the accumulator through valves that are computer controlled. Another set of valves release pressure from the wheels which sends fluid to the reservoir. When the accumulator pressure gets too low due to use, the pump adds fluid from the reservoir to the accumulator.

You can observe this sound by pumping your brakes, even in park. After a few pumps, accumulator pressure will be lowered to require replenishing.

 

The "bark" actually sounds like someone tooted a horn briefly; mine has never come back since the aux battery regained its full charge, so I still maintain that it's an electrical thing vs. a mechanical noise..

 

<div class='quotetop'>QUOTE(DanMan32 @ Oct 5 2006, 08:34 AM) [snapback]328445[/snapback]</div>

No sir! I thought we covered this earlier in the thread. This here is a BARK. A chirp if you will, but louder than most folks would call a chirp. It is the kind of thing that startles pedestrians near the car. I truly is that loud.

I had mine barking ealier this summer, and since returning from that trip, have not heard it again (though I do hear the pump all the time as usual).

 

Dan, I think you are describing the "snake" sound that I hear all the time. Like Darell said, the "bark" is really loud. It sounds almost like what others have said, sea-lion barks.

 

Yep....I'd say it's definately mechanical.....I'm not talking about the aquarium pump sound
(which is normal, I guess) ....I'm talking about the bark.
I too can make it do the sound by applying the brakes in various low speed situations...also
upon shifting from park to reverse, etc.
Does anyone know if there's a TSB out there addressing this issue?
If I bring it to my dealer I'd rather not get the "okay we'll play along to placate you" routine but
secretly "we think you're a nit picker who's hearing things" treatment.

 

I found this, http://www.alldata.com/tsb/Toyota/index-post.html

I search for brake, but don't see anything related to the Prius. Anybody got other more comprehensive TSB websites?

 

<div class='quotetop'>QUOTE(stealthgirl @ Oct 3 2006, 03:34 PM) [snapback]327586[/snapback]</div>

This weekend, I had my 2006 prius up in the Lake Tahoe area and it began honking/barking (6200 ft above sea level, ~30F). Sounds like it's coming from the front right to me in the drivers seat but the front left to my wife sitting in the passenger seat. It sounds exactly like what others are experiencing. As soon as I put my foot on the brake, there is a very short honk (< 1 sec). At first, I thought my boots were just wet and squeaking on the pedal as I went from the gas to the brake. The sound happens at a complete stop but unlike what others have described in this thread, it also happens when moving, especially in the 20-30 mph range. Above 40, I didn't really notice it. The odd thing is that as soon as we got back down to sea level and 60F weather, the sound has gone away. I'll bring it up with the dealer sometime but I was wondering if anyone else had reproduced it with a tech around and if so, what they said about it.

 

still have not heard this... if anyone's near us and can reproduce it, let us know.

 

Hmm. Today I was driving in 36 degree F temps through a parking lot and could have sworn that somebody near me was tapping his horn repeatedly. It sounded like very light honking, and that's what I believed it was until three minutes ago when I found this thread by sheer accident. Now I think I have experienced the same thing as some of you, while driving 15-20mph. Very strange!

 

Bad calipers or cylinders maybe? If they are squeeking, that would make noises even when not moving. Or bad solonoid valves.

 

<div class='quotetop'>QUOTE(DanMan32 @ Dec 30 2006, 12:49 PM) [snapback]368687[/snapback]</div>

That was my first reaction as well but as I understand it, there shouldn't be any conventional brake (caliper/drum) involvement in breaking until the car is below 8 mph. The honk/squeek happens immediately upon pressing the brake peddle at 20 mph and at 0 mph. As I said before, I haven't heard it since the car has returned to sea level and 60F weather. I'm wondering if it has more to do with something in the electric motor based braking system. On my old conventional cars, I'd always replaced my own brakes/rotors/calipers so I'm familiar with the conventional braking systems of the prius but I'm completely uninformed as to how the electrical component of the hybrid braking system works. Does the master cylinder pump brake fluid into the calipers immediately upon pressing the peddle at 20 mph? I have a feeling this is going to be a hard one to track down.

-Jeff

 

B) Bicycle brakes often make remarkably loud noises when they are slightly "toed" wrong or if the rims have been cleaned in acetone increasing the grippy nature of the surface.

So, maybe a trip to the bike shop is in store if the legendary Toyota mechanics can't fix it!

Bikes, the REAL source of clean transportation!

I've bicycled commuted for 23 years BP. Now my Prius is my bicycle mothership.

 

I have had the infamous barking sound also. I live in the bay area of california, very close to sea level. I have a 2006 with approximately 15,000 miles when the first incident happened. The first time I heard the 'barking' was after two weeks of very low temperatures (for california), cold and dry.

I put my foot on the brake, hit the start button, and then hear 3 or 4 'barks'. This has happened about 5 times just after the car turned on. Then it happened once while I was slowing down to a stop, but didn't start until the car reached 10 or 11 mph. Mine have always been 3 - 5 barks at a time. Thought I was going off the deep end until my friend was in the car during one barking session, and this time is was very cold and raining. :wacko:

I can't reproduce this sound for a tech as it has happened a few times over the course of two weeks, and hasn't been heard since!

I don't mind my car talking to me, but I'd at least like to know what it is complaining about!!

I hope someone finds out what it is. If you do, please explain.....

 

<div class='quotetop'>QUOTE(agenor @ Jan 2 2007, 10:30 PM) [snapback]369838[/snapback]</div>

I believe I have read that the mechanical brakes always move from rest to almost in contact with the rotors/drums when the brake pedal is pressed, even if only the electric brake is the only one actually being used at the time. This lets the mechanicals be "ready" if the driver suddenly required a much harder stop. Some cars were making noises at this point if the conditions were somewhat off from normal. The brakes would make a little contact instead of hovering just over the surface, makeing some noise. That is a very different noise then our "barking," but it indicates the mechanical brakes are doing something at 20mph as well as under 8.

 

Back in December of 2003 I was driving in the car with a Toyota service tech (mechanic) and unintentionally caused the car to make the sea lion bark noise. He kind of shrugged and then said he couldn't see anything wrong with it.

I know this doesn't help answer anyone's questions, but I have been ignoring it for years now and have never had any problems.

I still want to solve the mystery though.

~Andrew

 

My 2005 is also doing the bark sound when stopping (even the car is not moving). Took the car back second time this morning and they finally heard the bark. After 5 hrs of troubleshooting, they told me that it's a normal bark sound? They said I'm putting too much pressure to the brake. I have called the toyota service line 1800 331-4331 (option6) about this issue and they've gave me a ticket number. They told me that they will review and call me asap.

Everyone, pls if u have the same bark sound, please report to toyota asap so that they can fix this innoying issue.




<div class='quotetop'>QUOTE(stealthgirl @ Oct 3 2006, 07:34 PM) [snapback]327586[/snapback]</div>

 

<div class='quotetop'>QUOTE(galaxee @ Dec 27 2006, 11:21 AM) [snapback]367161[/snapback]</div>

Yeah, mine started this "barking" about a week ago. Its not too bad yet, at a normal stop light, usually barks two or three times. I let up on the brake and then reapply to try to get it to stop. I'd be glad for Galaxee to take a peek, actually, I still have to get down there and make an appointment to get my EBH installed.

 

great, rangerdavid! i'm sure DH will be interested to check that out.

we're out of town at the moment, but he'll be back at work next week friday.

 

No, it's more like the sound of a baby fur seal, when I club it Sorry, cheezy joke.
I've never heard anything like that in 53K miles. With so many in agreement, shouldn't the dealers know something?