brake pedal noise

ebod · Unread post by **ebod** » 27 Feb 2007, 21:59

What would cause my Xsara brake pedal to hiss ?

AndersDK · Unread post by **AndersDK** » 27 Feb 2007, 22:12

Leaking bellow on the pedal rod ?
Shown behind the vacuum servo device (thats for a 2.0 - may not fit your setup):

http://www.citroen-pr.net/catalogues/il ... 62B150.gif

Unread post by **CitroJim** » 27 Feb 2007, 22:16

Maybe it has a snake trapped in it

Seriously, is that the only manifestation? Is it not spongy? Hard? If it is otherwise OK then just one of those things but I'd say the master cylinder was perhaps on the way out. Is it leaking fluid at all? Do you have to top-up the master cylinder reservoir regularly?

A hiss has got to be caused by air. The servo may be unhappy, It could be something really simple like a poor joint where the vacuum pipe connects to the servo and braking movements flex the joint just enough to make it hiss.

My money is on the master cylinder though. They're not expensive considering their vital role, so replace it.

ebod · Unread post by **ebod** » 28 Feb 2007, 12:50

Brakes work fine ( well theres a big front disc squeek but its only the neighbours who notice...I can live with it )

I've had a few heavy braking moments recently to the degree when the hazard lights trip on automatically... and its been rock steady.

I know the usual script when a master/slave cylinder is on the way out and theres no sinking feeling or leaks.

So I reckon its an air leak. The noise is distinctly coming from the footwell and stops as soon as the brake is pressed.

I just wondered if there were any known problems with pipes/fittings or servo diaphrams..