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Unresponsive brakes this morning :S

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Steffgj, Apr 6, 2013.

  1. Steffgj
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    Steffgj Member

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    So this morning was driving to work and twice had a very hard brake pedal and very unresponsive brakes! Wasn't an issue as very few people are awake that early on a Saturday but want to get to the bottom of it before the misses and little one use the car.

    Seen a few threads online about water in the master cylinder due to blocked plenum drains but last time I checked them they were all clear.

    Other thought was could it be to do with the fact it was -1 outside? Calipers sticking?

    Any ideas?
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  2. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    My first thought was water ingress....
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  3. @udi A3
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    @udi A3 Site Sponsor Site Sponsor

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    Air vacuum pipe off, giving no servo assistance?
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  4. Steffgj
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    Steffgj Member

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    Thank you both, thought water ingress might be the case... Is it the water in there freezing and then causing an issue or just water in there full stop? (I know water in there full stop is bad but is it only going to be a serious issue when cold?)

    Will check vacuum pipe as that's a good shout but I'm guessing it might not be that as it was only intermittent.

    Anyone know if master cylinder is a pretty easy DIY or is it a garage job?
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  5. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    It's usually when the water freezes that you get the hard pedal issue. Was it a frost this morning where you were?
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  6. Steffgj
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    Steffgj Member

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    Very cold here this morning which would explain why I noticed it. Thanks James, another job to get done ASAP!
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  7. SL11CKK
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    SL11CKK Active Member

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    My servo gave up just a month ago and it was due to water. In my case the power went with it too. Also the brake pedal was very hard like you say.

    Went and bought a second hand servo which also came with the Master Cylinder although u don't need to change the master cylinder. Cost me £30 which was a damn good bargain considering they go for £80.

    Only tip I can give u is to also buy the vacuum pipe that goes into the servo as mines broke whilst getting it off.

    Also u need 1L DOT4 brake fluid.
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