MartijnAms

I have a brake noise that's similar to the one desribed in this thread, but mine's really audible. It's not 'screaming' loud, but at least the level of a normal conversation.
It occurs only when driving and braking to a (near) stop, i believe then always. All warning lights are working (light up when ignition to on), but are off when driving.

Sounds like an electrical pump with an airbubble, sort of buzzing, but louder than the 'other pumps' you can hardly hear. Location is from under steering column (i will check later to be sure).
Noise lasts for about 2-4 (?) seconds, always the same lenght.

I have a dealership look at it 5th of may, but a mechanic already drove it and couldn't place the sound (he never heard it- ok: he was young), so I don't have high hopes they will find the cause/solution. Two dealerships also listened to it and thought is was not something to worry about.

I just don't like the sound and I don't think its normal for such a quiet car!... I suggest to bleed the brake system, will that work and can it harm the delicate (&expensive) brakebooster assy?

I will bring it to the official Lexus dealership in Amsterdam (yes: Holland). I will post back results after may 5th, but maybe you guys can give us some tips to look at?
BTW: its a 98 GS300, 100Kmiles.

runyun

iTrader: (11)

My previous 2000 GS400 (80k miles) did that, was the Master Cylinder. Vibration and buzzing noise as you described. I did a search and most people said it was okay. I drove like that for a few weeks..then one day, I lost all brake pressure and almost ran through a red light.


Check out these threads:
https://www.clublexus.com/forums/gs-...ing-noise.html
(post #2)

https://www.clublexus.com/forums/gs-...n-your-gs.html
(post #5)

https://www.clublexus.com/forums/sus...d-booster.html

sivikvtec

Are you saying that your replacement unit does not do it? I'm pretty sure this is noise is normal for 98-00 models (unit was redesigned for 01-05).

MartijnAms

Thanks for the links, but I already seen them. They appear to be different noises and (hopefully) a different cause.
I don't have a screaming sound, or whining. It's like a pump motor, but louder than it should be in this kind of car (I guess).

A mechanic already drove it, he didn't think it was something dangerous or seriously wrong, but he hadn't heard this sound before (and he's an official Lexus mechanic).

So wednesday I will go to the dealership and check it out. Ik hope to find a direction on this forum, because I 'll be paying by the hour (normally I fix everything myself) plus I don't have high expectations we 'll find it by searching from scratch.

I will definitely post back any results.

runyun

iTrader: (11)

It did it about once everytime I got into the car.
When it was going bad, it happened more often.....maybe every 20-30 minutes.

The noise was like a pager on vibrate....except a little louder

MartijnAms

In my car it only happens when I stop (or nearly stop). It doesn't happen when driving or at startup.

rgarjr

iTrader: (1)

It's the master cylinder/ABS unit that craps put on these cars. Very annoying problem and only solution is to replace the part.

MartijnAms

Yes, I know these tend to break easily.
I hope mine is still 'fixable'. As I wrote: 2 dealerships plus a mechanic looked at it and all thought it wasn't something to worry about.

Ik hope to find a direction to look at, as a last resort i can replace the whole brake booster assy with one from a wreckers.

Given the descriptions above I hope somebody can give a clue to look at wednesday.

sivikvtec

Just be advised that there are many people on this forum with the exact same noise that occurs regularly while driving and when the car is first started. Of all of these people, only an extremely small percentage have experienced failure of a brake system component. Personally, my car has done it all the time since I purchased it over 10k miles ago without any adverse effects in braking performance. I would assume that when the cars were new that the pump was simply quieter and gets louder with age. Thats why we all notice it now on 10 year old cars with 100k plus miles.

Do not buy into the fear that something is actually wrong when only an extremely small percentage of people had a master cylinder or brake booster failure blamed it on the noise from the pump.

MartijnAms

Finally an update!
Before my holiday I should go to the dealership, but they didn't book my appointment. After about 2.500 miles I couldn't be bothered too much. I drove large parts on the German Autobahn (very fast) and through small roads in Poland.
Anyway, I made a Youtube movie, just for this sound problem.

Pls post back any thoughts, or questions (after reading all the posts about this brake noise).
I'm also interested if this sound sounds familiar.

YviE

iTrader: (3)

That's a weird sound, almost sounds like the ABS activating...

MartijnAms

ABS works though, everything feels normal. Read start post for description when it occurs etc.

YviE

iTrader: (3)

I have read your post. The sound is definately not normal.

Does the sound come from the pedal area only?

MartijnAms

I know its not normal: 2 Lexus mechanics drove and listened, couldn't place the sound. Though they claimed it wasn't something to worry about.
Of course I can bring the car for service, but I don't feel like it right now. Cost time money and maybe bad aftertaste. I try to find out more on this forum. Maybe somebody recognises the sound...
I can't pinpoint the sound exactly, it's from somewhere steering column.

sivikvtec

yea, um

that is definately NOT the normal sound everyone else has. good luck man!