98GS4me

First off, great forum. I searched but didn't find the symptom I experienced today.

I am getting ready to purchase a 98 GS 300 with 105,000 miles. So the car is in park position, I press the brake down 3/4 of the way, I hear this mechanical sound coming from around the brake pedal assembly. The sound is similar to when the steering wheel move into position when you first insert the key. I can feel small vibration on the brake pedal when the sound appears. The sound lasts for about 3 to 5 seconds and then go away. If I release the brake pedal, and then press down on it 3/4 again, it would make that sound again and after few seconds it would go away. Is there somekind of electric or hydraulic assist motor in the brake system that could make that noise? If not, any idea what could be making that noise / small vibration when the brake pedal is pressed down 3/4 way? Thanks in advance.

Mr Jokster

iTrader: (8)

Maybe a booster thing or master cylinder... Does the idle change significantly when you do so?

oh yea, and Welcome

98GS4me

thanks for the warm welcome

The idle does not change when I apply the brake. Would the brake booster or master cylinder make such a mechanical noise? Very much sound like a small electrical motor. The car brakes fine while driving BTW.

Mr Jokster

iTrader: (8)

Hard to make a good guess with out hearing it but no, they wont make that noise, HOWEVER, it sounds like what i hear on mine too. The fact that it does it with the brake may be coincidental... It comes from behind the dash right? A friend of mine (with a toyota camery) said that his does the same thing (its brand new). he said it has to do with the auto leveling of the car (or something of the such). I think one of the more experienced guys can tell you here with THAT description. I'm more than sure its not a bake thing if its the same sound that I hear. does it sound like a higher pitched can opener?

98GS4me

The noise is not real high pitch or loud. My main concern is if there is some kind of electrical motor that is part of the brake system, and it is tucked way under the dash (near the brake pedal assembly), it won't be easy to repair / replace. I've not heard of a auto leveling device, but I am not a expert when it comes to Toyota / Lexus either.

Mr Jokster

iTrader: (8)

Well, I dont mean HIGH HIGH pitch, just bit higher than the can opener wish I could hear it.

lexus ASM

They all do it, its your brake electronic brake actuator, they all do it after you start the car, its pressurizing the brake lines. When the dealership bleeds your brakes they use the tis scan tool to control the actuator and bleed each line separately.

(and im not shouting, im at work writing service and my caps lock is always on.. If you dont know, ask somebody.)

Mr Jokster

iTrader: (8)

um...no caps here!

98GS4me

when the electronic brake actuator activates (I am guessing when the brake pedal is pressed down almost all the way), is it suppose to be noticeable? Because I can hear it and feel it on the brake pedal. If this is normal, then I guess I am worry about nothing.

GS FONZy

iTrader: (6)