black_LS

Hi all - I bought my first GS a short while ago. I knew this car had an electronic actuator for a brake booster, but I was hoping it wouldn't give me problems.

While driving or idling, the unit (not sure if actuator, ABS, etc.) buzzes/charges/makes a noise that lasts about 3 seconds, but only after every 4th push of the brake pedal. So if you're sitting there continuously pushing the pedal, it will consistently actuate every 4th push.

Has anyone experienced this? Could this perhaps be normal? I will try to find a testing procedure for the unit/sensor.

black_LS

To add, there are no dash lights present.

DMPesso

Its your master cylinder on it way out, be careful. they are VERY expensive to fix, I would start with trying to find a used one or find another car because thats one of the worst issues to have with this car. What year how many miles and how much did you pay? You can TRY to first flush the brake fluid a couple times and see if that helps but that noise and pedal buzzing was always the master cylinder when that happened to any GS I have been in (I have been in many).

black_LS

I may be wrong, but it seems to me that it's more of a booster issue. I have no soft pedal issues.

I have never owned an electric assist booster - could anyone confirm how many presses of the pedal will cause it to kick on at idle?

DMPesso

booster is what I mean by master cylinder, arent those the same thing?

black_LS

After some more research, I've learned that it's normal for pump to run after 3-5 pumps of the pedal.

My problem likely lies in the pump or worn out rubber mounts holding the accumulator (causing a buzz).

DMPesso

I didnt even realize u said its when your sitting there and not driving. If your driving its your booster, if your parked this is normal.

samsmart

I get the same noise sometimes when I'm coming to a complete stop but never when I brake to slow then carry on. My brake pedal does depress quite a bit compared to newer cars I've driven, my brake disks and pads on the rear desperately need replacing though as the disks are warped. But now I'm a bit worried that this has going too. I don't get any juddering or anything in the brake pedal. But the car I do. I guess the best way to find out is replace the rear disks and pads and see what happens.

The noise doesn't sound bad. Sounds like a normal noise, a pump or something like that would make. Similar to a noise the central locking pump makes on an audi A8 I had.