When I hit the brakes I hear a weird eletrical\mechanical noise! What is it?
03-13-03, 09:40 AM
#1
Lexus Champion
Thread Starter
When I hit the brakes I hear a weird eletrical\mechanical noise! What is it?
This is on my 99 GS400 w/ 35k miles:
The qualifications for hearing this noise seem to be:
1- It has to have been at least 10-40 seconds since the last time I hit the brakes... sometimes longer... In other words, I'm really only guarenteed to hear this noise if I've been driving for a little while without hitting my brakes.
2- I have to hit the brakes with a decent amount of force. I mean, not like the kind of force that would throw you forward or cause the ABS to start working... not even close to that kind of force... I just mean I have to push the brakes more than just a feather's touch. If I just gently barely put my foot on the brake pedal, I won't hear it. But if I'm slowing down as in for a red light or to come to a complete stop in a parking space, I hear it.
3- It's a very soft noise... if I have the radio on at any decent volume or my windows down in an urban environment, it's doubtful that I'd hear it.
4- The noise is hard to describe, but for some reason it sounds like some sort of air pump filling up to me. It sounds similar to a loud waterpump or fuelpump... kind of an eletrical but also a mechanical noise. It seems to last about the same length of time every time... roughly 2.5 seconds, give or take a second or so. And at the end of the noise there is one single 'tapping' noise... like right as the noise finishes it sounds like somebody dropped a marble on whatever it is that was making the noise.
This is as best as I can describe it... so has anyone else noticed this noise? I'm sure that it's something related to the brakes, and probably is the sound of something at work doing what it should be doing, like maybe the brake booster? But I just found it odd the noise was loud enough for me to hear- especially in a car this quiet, it's very noticable. So has anyone else heard of this noise or does anyone have any ideas what it could be? I can mention it to my service manager at the dealership, but I just like to go into these sorts of things armed with knowledge so that he can't feed me a line of BS without me knowing.
The qualifications for hearing this noise seem to be:
1- It has to have been at least 10-40 seconds since the last time I hit the brakes... sometimes longer... In other words, I'm really only guarenteed to hear this noise if I've been driving for a little while without hitting my brakes.
2- I have to hit the brakes with a decent amount of force. I mean, not like the kind of force that would throw you forward or cause the ABS to start working... not even close to that kind of force... I just mean I have to push the brakes more than just a feather's touch. If I just gently barely put my foot on the brake pedal, I won't hear it. But if I'm slowing down as in for a red light or to come to a complete stop in a parking space, I hear it.
3- It's a very soft noise... if I have the radio on at any decent volume or my windows down in an urban environment, it's doubtful that I'd hear it.
4- The noise is hard to describe, but for some reason it sounds like some sort of air pump filling up to me. It sounds similar to a loud waterpump or fuelpump... kind of an eletrical but also a mechanical noise. It seems to last about the same length of time every time... roughly 2.5 seconds, give or take a second or so. And at the end of the noise there is one single 'tapping' noise... like right as the noise finishes it sounds like somebody dropped a marble on whatever it is that was making the noise.
This is as best as I can describe it... so has anyone else noticed this noise? I'm sure that it's something related to the brakes, and probably is the sound of something at work doing what it should be doing, like maybe the brake booster? But I just found it odd the noise was loud enough for me to hear- especially in a car this quiet, it's very noticable. So has anyone else heard of this noise or does anyone have any ideas what it could be? I can mention it to my service manager at the dealership, but I just like to go into these sorts of things armed with knowledge so that he can't feed me a line of BS without me knowing.
Last edited by Threxx; 03-13-03 at 09:40 AM.
03-13-03, 10:07 AM
#3
Lexus Champion
Thread Starter
Originally posted by Dex
Sounds like the master cylinder pressurizing. Check you fluid yet?
Sounds like the master cylinder pressurizing. Check you fluid yet?
Would having too much fluid cause it to make this noise?
The dealer just had my car in for the 30k mile service... they claim they replaced the brake fluid, and it was making this sound both before and after the service. So I wonder if there was too much in there both times?
03-13-03, 07:23 PM
#4
Forum Administrator
iTrader: (2)
Could it possibly be your ABS engaging? Do you feel any pulse through the brake pedal?
03-13-03, 08:08 PM
#6
Lexus Champion
Thread Starter
Originally posted by GSquicksilver
it's the ABS and VSC self test. no worries, just built in routine checkups your car does on its own. read your owners manual and it will tell you.
it's the ABS and VSC self test. no worries, just built in routine checkups your car does on its own. read your owners manual and it will tell you.
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03-16-03, 08:47 PM
#8
Lexus Champion
I had that same question when I first got my gs almost 2 years ago. The sound is sort of like a little whirling pump sound, with a mechanical thunk at the end. It occurs whenever you've used the brake (minor braking) for a little bit, or for some long down hill braking. I think it has something to do with keeping the brake pressure up, perhaps because this is a mechanical than a vaccuum brake boost system. The dealer told me it was normal at the time.
06-03-04, 07:01 PM
#9
Lexus Test Driver
Sorry to bring a one year old thread back, but I think this will be helpful for new owners of the GS.
I have the same exact thing....I never noticed when it happens, I think mine happens even when I'm stopped at a traffic light.
I'll start noticing if it only happens after I hit the brakes. And I'll pay attention to see if there's a "click" sound after the end of the mechanical motor buzzing sound.
Has anyone else notice this sound?
I have the same exact thing....I never noticed when it happens, I think mine happens even when I'm stopped at a traffic light.
I'll start noticing if it only happens after I hit the brakes. And I'll pay attention to see if there's a "click" sound after the end of the mechanical motor buzzing sound.
Has anyone else notice this sound?
06-04-04, 12:41 AM
#10
Sound..
My GS makes this sound aswell, i'm sure its not a big deal..something to do with the brakes, and pressure (not a self test as i recall)...
On a side note, my brother's 1990 Supra Turbo also makes this sound, with the same thunk in the end.. probalby just a Toyota thing..
On a side note, my brother's 1990 Supra Turbo also makes this sound, with the same thunk in the end.. probalby just a Toyota thing..
06-04-04, 07:14 AM
#11
Lexus Champion
Thread Starter
Well my car still does it and still no issues with the brakes... so I guess it's OK!
My only concern is that most cars you hear this sound in have issues with their brake syst***s master cylinder losing pressure... and they have to constantly repressurize it.
As much as this thing goes on and off I gotta wonder if it might wear out some day?
My only concern is that most cars you hear this sound in have issues with their brake syst***s master cylinder losing pressure... and they have to constantly repressurize it.
As much as this thing goes on and off I gotta wonder if it might wear out some day?
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