hissing noise from brake servo

[haigh]

Vauxhall Corsa 1.4 petrol 8Valve Automatic R reg. 1997

Brakes have never been a problem. and passed MOT(with this noise) last year. But.
been getting this hissing noise- sounds like escaping steam- from brake vacuum servo area, specially when you take your foot off the gas: when you accelerate, or brake, noise, disappears temporarily.

like I said ,Brakes ok so I must be getting a vacuum. Anybody got any ideas?

haigh

[craig green]

Is this with the engine running, heard from the cockpit?

A partial vacuum loss wont affect the servo assistance, or you'd feel it. But if there is a vacuum loss, it wont be doing the engine/induction much good. Get it looked at & sorted. Check the vac lines obv.

[haigh]

only with engine running, also can hear it from inside car, not affecting braking. brake, or put your foot on the gas, noise stops

[meritlover]

A partial vacuum loss wont affect the servo assistance, or you'd feel it. But if there is a vacuum loss, it wont be doing the engine/induction much good.