gs-ireland

Hello,

I have a late 98 GS3 and my ABS/brake hydraulic booster tops its pressure up every 5 mins or so driving around the town with start-stop driving.

Every few minutes and depending on how hard I press the pedal I can hear the small pump run and pump for around 5 secs then a relay click to turn off, sounds like whirrrrrrrrr...click'. This also makes the headlights dim slightly with the large current.

Does happen to other users as frequently as this?

Joe C

I'm guessing it's the same sound that I hear too. Seems to be normal.

chinkster

i hear this too... didnt know what it was tho. you sure this is what it is? seems to be coming from my driver side in the dash somewhere. i have a 98 gs400 tho, i dont know if that matters.

chuckb

totally normal. how frequent it depends on how much you use your brakes. you'll notice it in drive-throughs when your foot's on the brake a lot.

btw-my headlights don't dim when it kicks on, your alternator may be weak.

JeffTsai

iTrader: (1)

My car does it as well and it's brand new. It's completely normal. The brake booster should come one with every 3-4 presses of the pedal. Just try it while your car is parked. The pump should kick in after the 3rd press or so.

gs-ireland

With 3 light or 2 heavy presses it does activate.
It also takes about 10-15 secs to charge up when I first start the car in the morning. Does this sound ok?

Is there any test I can do to make sure that it is not starting to fail?

skeet94

It's a perfectly normal sound . My Aristo does it too. When we picked up the car from the previous owner, we were pretty much "scared" that something was already wrong with the car...then came to realise it's PERFECTLY fine! .

Mine does it in town driving every 4-5 stops (soft braking).

jonathancl

How loud is the click?

I don't remember hearing mine when I bought the car at 30k mi, but I know I have been hearing it since about 75k.

From within the cabin, it's a pretty loud click these days.
Will replacing the relay affect it?