Results 1 to 13 of 13

Thread: High pitch whine coming from brake booster

  1. #1
    Join Date
    Sep 2009
    Location
    Dublin, CA
    Posts
    12
    My Cars
    2002 325CI

    High pitch whine coming from brake booster

    Hi,

    I posted earlier about a high pitch whine. I got it narrowed down and was wondering if you guys could help:

    - High pitch whine that is noticeable in the cab, and also outside. Coming from the brake booster/fluid assembly.
    - Stops when brake pedal is depressed (even the slightest pressure will stop it)
    - Is not related to stereo, fan, A/C, belts, etc.
    - Will continue to whine for 10-20 seconds even after the car is shut off

    I do think I need to have my brakes checked since the car is pulling to the right and left on slow speed braking. I also have a squeal in the brakes on certain occasions.

    Can anyone diagnose this high pitch whine?

    Can I got to a local midas to service the brakes? What kind of prices should I be looking at?

    Thanks

  2. #2
    Join Date
    Jan 2009
    Location
    Williamsburg, VA USA
    Posts
    22,932
    My Cars
    2004 ZHP 6MT
    Quote Originally Posted by alloy171 View Post
    Hi,

    I posted earlier about a high pitch whine. I got it narrowed down and was wondering if you guys could help:

    - High pitch whine that is noticeable in the cab, and also outside. Coming from the brake booster/fluid assembly.
    - Stops when brake pedal is depressed (even the slightest pressure will stop it)
    - Is not related to stereo, fan, A/C, belts, etc.
    - Will continue to whine for 10-20 seconds even after the car is shut off

    I do think I need to have my brakes checked since the car is pulling to the right and left on slow speed braking. I also have a squeal in the brakes on certain occasions.

    Can anyone diagnose this high pitch whine?

    Can I got to a local midas to service the brakes? What kind of prices should I be looking at?

    Thanks
    They're gonna see "BMW", then lube you up....that's all I'm saying. Maybe not. Maybe if you dress like a bum, and tell them the car is your grandmothers....they'll only.......I'm at a loss for words to descibe...lol

    by Dane Wilson, on Flickr

  3. #3
    Join Date
    Sep 2009
    Location
    Dublin, CA
    Posts
    12
    My Cars
    2002 325CI
    anyone other than the idiot above care to comment?

  4. #4
    Join Date
    Sep 2009
    Location
    Dublin, CA
    Posts
    12
    My Cars
    2002 325CI
    any help?

  5. #5
    Join Date
    Sep 2008
    Location
    alabama
    Posts
    5,537
    My Cars
    2002 bmw 325
    there is a vac line that runs on the inside of the drivers dash, down by a/c case. i have had them makes noises on a few occasions due to a pin hole. The diff is you cant hear it outside only on the inside.

    easiest way to diag it remove the brake cooster line and plug it up. crank car and see if noise goes away. it it does than you may have a leaking diagraphn in the cylinder, if still there, you can search for the noise else where.

    I have not replace a cylinder on a 3-series before for noises, due to wrecks i have done a few. But i guess anything is possible.

    as far as brakes go, anybody you trust can do them. i recommend factory stuff due to no noise and you know the car will stop.
    02 BMW 325
    13 MB GLK350
    94 GMC sonoma 4x4 - hpd30/8.8 - toy
    15 MB GLA250 (wife's)
    01 Pontiac WS6 - Garage Queen
    12 RAM CC Hemi powered - new DD

    GOIN BROKE BUT N STYLE

  6. #6
    Join Date
    Sep 2009
    Location
    Dublin, CA
    Posts
    12
    My Cars
    2002 325CI
    So a leak from the diaphragm inside the brake booster...

    Is a replacement of the cylinder possible to do myself? How much would I be looking at with the dealership?

    Can anyone think of any other issues this could be; the whining noise is very noticeable after the car has been stopped and started multiple times throughout the day, almost like the brake fluid is warming up.

  7. #7
    Join Date
    Jan 2009
    Location
    3rd Rock
    Posts
    1,027
    My Cars
    Some
    If the noise goes away when the brake pedal is pressed, then I would be amazed if it wasn't a failed brake booster.

    I have seen several of them fail like this on e46's.

    Please don't take your car to midas. Try a reputable indy bmw specialist. If their prices are too high, then this might not be the car for you.

    Or even better, do it all yourself. Brake booster replacement is a pita job though.

  8. #8
    Join Date
    Dec 2004
    Location
    Mill Creek, WA
    Posts
    3,972
    My Cars
    98 740iL, 01 Suzuki TL10
    Bumping this thread as my mom's car is doing the same thing. Sitting at idle and it sounds like a dog whistle, press the brake pedal ever so slightly and it goes away. Seems excessive to replace an entire brake booster for a simple gasket leak.

  9. #9
    Join Date
    Dec 2004
    Location
    Mill Creek, WA
    Posts
    3,972
    My Cars
    98 740iL, 01 Suzuki TL10
    Bump

  10. #10
    Join Date
    Jun 2009
    Location
    Vermont
    Posts
    30,858
    My Cars
    97 328i Vert, 98 M3 Vert
    Nobody mentioned a gasket.

  11. #11
    Join Date
    Dec 2004
    Location
    Mill Creek, WA
    Posts
    3,972
    My Cars
    98 740iL, 01 Suzuki TL10
    * diaphragm

  12. #12
    Join Date
    Jun 2009
    Location
    Vermont
    Posts
    30,858
    My Cars
    97 328i Vert, 98 M3 Vert
    Quote Originally Posted by m5james View Post
    * diaphragm
    Well that diaphragm is what makes the whole power brakes work. It's inside the booster housing. It's not replaceable. The booster is a sealed unit. It will keep deteriorating.

  13. #13
    Join Date
    Dec 2004
    Location
    Mill Creek, WA
    Posts
    3,972
    My Cars
    98 740iL, 01 Suzuki TL10
    I'd just hoped it could be something as simple as this:

    http://www.ebay.com/itm/150677356537

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •