hearing air after I take foot off brakes...2000 328i

So... for awhile now theres been this air type noise coming from the brake pedal area... it used to only do the air noise when i took my foot off the brake but now it does it constantly and only stops when my foot is on.
I took it to les scwab and they do not go that deep into the car but the said they did a brake check & said they are fine..



Then, when I was getting my oil changed they guys said I got a big problem and its gonna cost me big bucks to fix.

Any help, suggestions ??

Make a video of the sound/problem and we can help.

Aside from master cylinder seal overhaul (or swap) one thing you might try is to replace or flush the brake fluid.

Aside from that, air is going through some orifice somewhere, so it's kind of hard to diagnose.

Try a good Indy, maybe via www.bimrs.org.

Originally Posted by tiffanycoates

Then, when I was getting my oil changed they guys said I got a big problem and its gonna cost me big bucks to fix.

Any help, suggestions ??

RUN, don`t walk, away from this place....

here's the video ! hope this works

this is what it sounds like

& Thanks so much for the help so far!

Ok that is most definitely not normal.

Hard to tell but it almost sounds like a disconnected main vacuum line.

Power brakes work in theory by taking vacuum (low pressure) from the intake to a "booster". In effect the brake pedal acts as a modulator or control to this pressure to translate your (weak) foot power to the (strong) vacuum power of the intake. Hence the term "power brakes".

This all happens in the brake master cylinder, which ties the vacuum, the hydraulic reservoir in the engine and the brake lines. In practice this is all fiendishly complicated by abs dtc etc etc but essentially it all works like this.

So, based on the sound, it seems there is a significant leak in the vacuum.

Are your brakes hard to press I e do you have to stomp on the pedal to get good braking?

Originally Posted by Llando88

One thing you might try is to replace or flush the brake fluid.

www.bimrs.org.

First Step: do the above with a proper brake bleed.

Originally Posted by danewilson77

First Step: do the above with a proper brake bleed.

Concur. It is possible there is some gunk somewhere that shouldn't be.

Good power bleed and suck via the wheel cylinders is never a bad idea.

I always used Ate SL.

OP - how long has it been since the brake fluid was serviced/replaced?

The brakes work just as brakes should, and I had them replaced at the end of july 11'

Originally Posted by tiffanycoates

The brakes work just as brakes should, and I had them replaced at the end of july 11'

Did they flush the fluid?

I have never had the brake fluid serviced or replaced, so I'm thinking I should start there... just got the new brakes etc put on during this past summer.
Thanks so much for the advice

Forgot to add- if you go out and look at the brake fluid reservoir, what color is the fluid? (hopefully very light/almost clear).

Originally Posted by tiffanycoates

I have never had the brake fluid serviced or replaced, so I'm thinking I should start there... just got the new brakes etc put on during this past summer.
Thanks so much for the advice

Ok it's possible to replace brakes (I assume you mean pads and rotors?) and skip the brake fluid.

If you are handy with tools, check the E46 wiki or we can walk you through it (Fast Bob could do it in his sleep I bet lol).

Otherwise get in touch with a good independent BMW mechanic.

Im going to go check this fluid right now

Its nice and clear

wow thanks for pointing me in this direction, I can't believe I haven't looked at this wiki until now.

Originally Posted by tiffanycoates

Its nice and clear

Hm kind of points to a mechanical defect allowing air to pull where it should not.

At this point you probably need to get the car checked out by someone who you can trust. Given the noise and the fact it happens all the time, chances are good it can be diagnosed and put right fairly quickly.

Good luck.