1.9tdi Brake Pedal Hissing?

[wackojackouk]

Hi guys

 

Never noticed it before but today when I pressed the brake pedal I could hear a hissing noise like air was being pumped - I noticed there is a little pump thing under the pedal which I never noticed before and pumped the brake a few times and could hear air being pushed through this.

 

Is this normal? - Brakes don't feel any different from normal and did an emergency stop which was fine.

 

I was playing around with some fuses yesterday trying to sort out an issue with the DVD player so wonder if this could have an effect.

 

What with this, the clunking nose, the aux heater (again) - do these cars ever run without problems?

 

Any thoughts regardless?

 

Cheers

 

WJUK

[roy202]

Hi guys

 

Never noticed it before but today when I pressed the brake pedal I could hear a hissing noise like air was being pumped - I noticed there is a little pump thing under the pedal which I never noticed before and pumped the brake a few times and could hear air being pushed through this.

 

Is this normal? - Brakes don't feel any different from normal and did an emergency stop which was fine.

 

I was playing around with some fuses yesterday trying to sort out an issue with the DVD player so wonder if this could have an effect.

 

What with this, the clunking nose, the aux heater (again) - do these cars ever run without problems?

 

Any thoughts regardless?

 

Cheers

 

WJUK

Hi the air leak on the pedal sounds like the servo has got a air leak, mine does exactly the same, its been like it a year now and has got no worse, when it does i will change it. as it is the brakes are fine and ive got no probs but it should be changed really.

[wackojackouk]

Hi the air leak on the pedal sounds like the servo has got a air leak, mine does exactly the same, its been like it a year now and has got no worse, when it does i will change it. as it is the brakes are fine and ive got no probs but it should be changed really.

 

Cheers mate. Yeah it's a weird noise - sounds like air is being pushed out of a pump if you know what I mean.

 

She is going into the garage in a couple of weeks (again) as I need a couple of things doing/looked at and will mention this then.

[Ivor_E_Tower]

Diesels don't have a servo... there's no inlet manifold vacuum (that's what I read some time ago, anyway). Diesels therefore use a pump to provide the braking assistance, hence the pump-like noise you can hear as there is probably an air leak in the pipework somewhere.

[marinabrid]

it cost me

[seatkid]

Diesels don't have a servo... there's no inlet manifold vacuum (that's what I read some time ago, anyway). Diesels therefore use a pump to provide the braking assistance, hence the pump-like noise you can hear as there is probably an air leak in the pipework somewhere.

Yes they do have a servo - but as you point out they use an engine driven vacuum pump instead of the petrol inlet manifold to generate the vacuum (which is also used for the turbo control system and some a/c heater control functions on non-cc models).

 

Although pipes are known to crack/perish and leak, if you can hear the hissing in the car its more likely to be the servo. IF YOU HAVE A MODEL WITH BASIC A/C (I.E. NOT CLIMATE CONTROL) CHECK THE CONTROL PANEL. SOMETIMES A VACUUM PIPE BECOMES DETACHED FROM THE CONTROL AND HISSES.

 

From the number of previous posts on the subject, I fear this is becoming a common fault on older cars.

Edited November 15, 2010 by seatkid