Should I be worried...brakes "hissing"

[ade]

Right...

I've not used my car for a few days mainly due to the cold weather but I'm due back at work tomorrow so thought I'd start her up...

1st trime no worries however when I pressed the brake pedal there was a strange hissing noise coming from the passenger footwell area. As long as pedal weas pressed it continued to hiss. Now I know this is where the back of the servo/master cylinder feeds in to the cabin and is connected to the brake pedal push rod but should it hiss?

The car was still cold, the brake pedal went pretty hard but when pressed the rev rose by about 500rpm. I reversed a little and applied brakes - and car stopped - pulled forward and same again.

Checked engine bay and servo area and all hoses are connected, not split and the reservoir for fluids is full.

Any ideas? I did notice it the last time I took the car out but brakes seemed okay.

Ade

[brake-dust]

my iveco does this, no idea why but never had a problem

[Welsh Dan]

Its a vaccuum leak ade. It might be the rubber grommit where the pipe meets the servo.

[AlexW]

New servo probably though?, cold weather wont have done it much good

[ade]

rubber grommet is new - less than 6 months old. Servo has been reconditioned. I'm hoping its because cars been stood for a few days and temp hasnt been above freezing...

I'll take it for a spin round some quiet roads and see how it responds...

[craig green]

Hmmm. Are you getting servo assistance?
I would have said the sealing gromet aswell. Hope its nothing to worry about pal.

[GRUNT 16V]

as above check your grommet also thinking about it servos wer fairly common too

[ade]

checked grommet - totally split. Which p1ssed me off as its less than 6 months old!
So changed for spare grommet - still no good
so changed servo unit - all sorted!

Also ordered 3 more grommets - £5 each! come with little right angle corner bit though...

[Mazz]

Check that the one-way-valve is ok too Ade, only a few quid but it will save you getting a new servo..