Brake Hiss ?

[Gold Pirate]

Just noticed on tick over that when I press the brake pedal on my Blingo I can hear a hiss? Doesn't do it every time and brakes seem to operate normally when driving. Could it be a servo leak ? .....any thoughts !

[citronut]

if it where a servo leak you would notice the the need to put more efort into pressing your brake pedle,perhapps you dont allways hear it over diferant sounds from the radio,also if you had a vaccum leak the engine revs would be eratic
regards malcolm

[Gold Pirate]

Cheers for that Malcolm !

[jeremy]

If you have a diesel the vacuum for the servo will be provided by a pump and the idle will not be affected by air leaks. Diesels are not affected by air leaks on the inlet side as they work on the free air principle and the fuel is introduced directly into the combustion chamber.

[Gold Pirate]

cheers jeremy it is a diesel..i'll have a look for leaks etc today !

[citronut]

even so your brake pedle presure would be afected by an air leak between the vaccum pump and or in the servo
regards malcolm

[eskimoigloo]

Hissing is normal! It is the air leaving/entering the brake servo, probably more likely to be a bit of sound profing fallen off so you can now hear it!
Chris

[Gold Pirate]

cheers chris, spent frustrating hours looking for a leak....i think your right!