Hissing noise from brake pedal

  1. Regular Poster Joined: Sep 2011 Patras Greece Posts: 352 Ford Focus 2.5 ST Citroen Saxo Vts 16v race car
    #1
    The car is a 205 with a 1.6 16v gti/vts conversion , saxo/106 front and rear disk brakes

    Before and after brake fluid change , when pressing the brake pedal you hear a hissing sound like air is leaking ,
    Brake pedal feels quite soft in the beggining but car brakes perfectly!

    Anyone got an idea what it could be??
    Cheers Alex
  2. Saxperience Forum Bum Joined: Apr 2013 Jarrow Posts: 4022 2003 Icelandic Grey 16v VTR 1991 Daihatsu GTti
    #2
    Lipped disc?
  3. Regular Poster Joined: Sep 2011 Patras Greece Posts: 352 Ford Focus 2.5 ST Citroen Saxo Vts 16v race car
    #3
    Sorry didn't explain it correctly , sound is made even when car is stopped with engine on
    When engine is off you can't hear it , could it be domething to do with the servo??
  4. Newbie Joined: Jan 2014 Aylesbury Posts: 6 Amazon Mk1 VTS track car 306 Estate
    #4
    Sounds to me like the servo could be leaking.
    Is it corroded in any way?
    It's a common problem on 306's so could relate to your car
  5. Saxperience Forum Bum Joined: Oct 2010 Here and there. Posts: 3372 205 GTi
    #5
    Does it do it as you press the pedal, then stop when you have the pedal down??

    In some cars that's normal. If your pedal isn't rock solid, i wouldn't worry about it.

    My car does it, but its a constant hissing until the brake pedal is pushed, so opposite to you. Mine needs a new servo as it has an air leak.
  6. L-plater Joined: Aug 2009 Burton on Trent/Sheffield Posts: 83 Citroen Saxo 1.6 VTR
    #6
    possibly servo seal has gone and is leaking
  7. Saxperience Forum Bum Joined: Jul 2010 South Wales Posts: 3078 ZX 16v, 205 GTI, 309 Goodwood, 405 MI16.
    #7
    sounds normal, you will lose vacuum if you press the brake with the engine off and the pedal should go firm.

    if you turn the engine on with your foot on the pedal it should drop a little as the vacuum builds up again.
  8. Saxperience Post Whore Joined: Apr 2011 Posts: 9100 Amazon green VTR 16v, Inferno RS clio 182
    #8
    Some cars hiss from the pedal until you've pumped it up without the engine on


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  9. Regular Poster Joined: Sep 2011 Patras Greece Posts: 352 Ford Focus 2.5 ST Citroen Saxo Vts 16v race car
    #9
    Thanks for the replies ,
    sound is made when engine is running so obviously the servo has vacuum
    Brake pedal feels a little soft at the beggining until roughly 1/4 of the travel when the noise is made whilst applying pressure to the pedal ,
    then till half the pedal travel its nice and stiff and brakes pretty well too ( so no problem with brake pump or air in brake pipes )

    If the servo has a vacuum leak would that mean that when the vacuum is lost the brake pedal becomes a little harder but not as hard as when the engine is off.

    Sorry but never had a problem like this before , and its not even my car but still getting my head in with it!!