Porsche Enthusiasts Club Forum

Hi all,

Looking for a second opinion when I press the brake pedal there is a hissing sound in the footwell so I believe this points towards the servo is leaking

Thanks Ryan

Hi, a hiss when operating the pedal doesn't always mean a leak (air or vacuum) as what you are doing there is opening a valve and some pressure equalisation is taking place inside the booster chambers, sometimes this is just operationally noisy (especially when the motor is not running). However, sometimes these components do leak, so the best thing to do is carry out some basic operational tests - they only take a minute or two. I found a brilliant PDF about brake booster operation on this site:

http://www.autoshop101.com/forms/brake05.pdf

Download that - its a good read and has simple tests on all aspects of booster operation, etc. Hope it helps.

Thanks will have a go at that and see how we go

Cheers Ryan