Volkswagen Sharan (1995 - 2009) - 99 1.9 Air hissing from brakes in car

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Wed 28 Oct 2009 10:06
99 1.9 Air hissing from brakes in car - vwdel
I have an air noise sometimes coming from the brake pedal, but it goes if I gently "TAP" the pedal.
It doesn't seem dangerous, what is the problem and is it expensive to cure, please.

many thanks Del.

Edited by vwdel on 28/10/2009 at 10:08

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Wed 28 Oct 2009 10:35
99 1.9 Air hissing from brakes in car - Dynamic Dave
Brakes, air hissing? Sounds like your servo is leaking.
It doesn't seem dangerous


I would seek a 2nd opinion - preferably from a mechanic and sooner rather than later.
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Wed 28 Oct 2009 15:44
99 1.9 Air hissing from brakes in car - Peter D
Brake servo failure immanent. Is it dangerous, Yes. Suddenly you could be reduced to no servo assistance and you could/will smack into something or somebody. Regards Peter
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Wed 28 Oct 2009 15:53
99 1.9 Air hissing from brakes in car - bathtub tom
I've had experience of a servo 'shrinking' due to corrosion, effectively making the rod that passes through it longer. This had the effect of permanently applying the brakes.

What's your current fuel consumption like?
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Wed 28 Oct 2009 15:56
99 1.9 Air hissing from brakes in car - bathtub tom
I've just noticed your earlier thread:

www.honestjohn.co.uk/forum/post/index.htm?m=921470...#

Perhaps the problems are linked?
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Wed 28 Oct 2009 15:59
99 1.9 Air hissing from brakes in car - vwdel

I asked a driver who has had VW for a few years, he said that it was a valve that lets out excess air and just noisey, but I think I should get it checked out.
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Wed 28 Oct 2009 16:16
99 1.9 Air hissing from brakes in car - Number_Cruncher
At least one of the two internal valves which control the operation of your brake servo is sticking. Modern servos aren't repairable, so, you need to replace the servo.

Sometimes, servos can be damaged by leaking master cylinders, so, check for the presence of brake fluid in the brake cylinder "side" of the servo's diaphragm chamber, and, if any is found, renew the master cylinder too.

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