Hissing noise from around the brake pedal

[cvselman]

Only noticed over last few days. Hissing noise from around brake pedal, stops when pedal depressed. Brakes seem to work fine, fluid level good. Is this the servo and should #I be worried?

Carl

 

[Henry]

does sound like the servo (it's normal). it should only ever stop hissing once you've exhausted the vacuum (with the engine off).

try this: immediately after having turned off the engine, pump the brake pedal half a dozen times - you should initially hear it hiss with every pump and then it'll stop doing so once you've exhausted the vacuum in the servo. the brake pedal should now feel much firmer. now, with your foot pressing the pedal down, restart the engine: the pedal should slowly sink a little as the vacuum builds back up. your servo's fine if this all works.

 

[cvselman]

Thanks - I did that and all seems fine but... still have hissing from around pedal, very distracting as goes on most of the time, have to play about with tapping the pedal to stop hissing whilst driving. Must have some kind of leak even if the server is fine. any suggestions.

Carl

 

[Henry]

the hissing is normal; whilst the engine is running you will get hissing from the brake pedal (whilst it's being depressed)

 

[chewitt]

a snake wrapped round ur pedals?

 

[clio_luke]

yeah, i believe its normal for the hissing (air) sound when you press the brake pedal.

 

[Sean6545]

Its not normal for brake servos to leak there vacuum. Get it looked at if I were you.

 

[Henry]

is it not possible it's just the rear chamber of the servo filling with atmosphere as the piston travels down it?

or is that inaudible? i'm sure it's been audible in some of the cars i've driven; will have to see if i can hear mine in the morning

 

[foxspeed]

should only "hiss" when the pedal is pressed - if it does it all the time its faulty

 

[Henry]

:dead: i've just re-read the OP's last post and now realise that he's complaining of constant hissing o x10 - apols for confusing things).

 

[cvselman]

Hi guys, thanks for the help. I get the hissing most of the time, it will stop if the brake pedal is depressed as little as a couple of mm. Even if I press the clutch pedal. Maybe the whole pedal assembly is loose slightly? I'm in Lanzarote and work manuals are like chocolate teapots. Anyone have a diagram of pedal assembly and connection into server they can scan and send to me at carl@vanselman.com
Thanks