We run a FL Octavia estate (59 plate) 1.9 pd as a pool car at work. Currently on 96k and going well.

However, it's just started making a hissing noise from the pedal area today. Noise stops when brake pedal touched. Comes back when not touched. Braking seemingly unaffected.

Any suggestions?

Is the Air con operating when this happens?

The air con was on when it was happening this afternoon.

Any further ideas? Could it be the servo?

It could be the servo , without actually hearing it,  it is hard to determine. If it was it means that the servo could be faulty/or the brake pedal is pressing on the servo rod just enough to let air in without actually operating the brakes. Brake pedal return spring broken ? . Something stopping the brake pedal fully releasing?

 

Curious !

I've seen this on a Volvo V70 (2001 plate) where it hissed on pressing the pedal and this was a duff servo, I know yours opposite.

 

I asked about Air Con as I had a hissing on Octy mk2 vRS that I only noticed at low speeds and it turned out to be low refrigerant, regas sorted it. 

 

Let us know how you  get on

It seems to have gone away now all by itself. Odd!