when I take my foot off the brake in my 2001 avensis auto I get a hiss coming from the servo. this can only be heard inside the car not under the bonnet. just touching the brake slightly will cause the hiss to stop but once the foot is removed the hiss returns. Brakes work fine. Anyone know how to fix. It is very irritating. taxirank
If any of the climate control system uses engine vacuum, this may be the source.
Make a rolled paper tube and listen under the dash to locate the source. I would not expect vacuum hoses related the brake booster to be routed inside the cabin, so I'd suspect that the brake booster diaphragm has a small hole that's sucking air.
SJD
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