Brakes hissing noise advice please

[ToneyCaroney]

Hi All,

Out in the Griff today and it has started making a hissing noise when pressing the brake pedal.sounds like air escaping from something. Pedal also seems to need a bit more pressure applied. If I press the pedal with engine off it firms up as usual and servo kicks back in ok after starting but hissing returns.

Cheers.

Edited by ToneyCaroney on Sunday 26th February 15:36

[ToneyCaroney]

Thanks Mike. Sage advice as normal

[ToneyCaroney]

Thanks all,

So I had a nose around this morning and the I don't seem to be losing brake fluid - reservoir is still a few mm from the top. I've looked a the servo as best I can by crawling into the footwell. It looks to be in good condition (apart from a bit of yellow gunk that seems to have been brushed on). Feeling around it (as much as I can get too) it feels solid and surface is smooth, i.e no rust. No brake fluid leaks into footwell either.

Pic of (part) servo.

[ToneyCaroney]

I can give that a go but won't I need my head right next to the pedals!? Or, is there another way to get near the servo? Cheers.

[ToneyCaroney]

Update on this for anyone else who might have the same: was indeed the servo itself. Now replaced along with master cylinder as a precaution and all is well.
Cheers to all (not Mike!) for the helpful suggestions