Iced brake servo?

[PhatBob]

Sorry that my first post is a problem,
Having had this problem:
http://www.audi-sport.net/vb/showthread.php?t=63927
And solving it by removing the grommets I've now found its caused a new, more worrying, effect:

Water has obviously got into something because on an icey morning the brakes seize on when the pedal is pressed. Normal function returns when the temperature rises

The servo activates fine - it just doesnt release properly.

I'm wondering if there's a vent or non-return valve that could have been contaminated with water - theres no chance of it getting enough warmth and air circulation to dry out.

Once the brakes are defrosted the function is normal.

Does anyone have any suggestions on which component will have failed?

 

[evomaster3000]

I'd say u got water in the servo judging from the previous issue u had, either take it out and heat it up or replace thos they ain't cheap!, i've changed mine before, not an easy job as u gotta get up in the drivers foot well, but a case of removal and heating the thing up should evaporate any water in there.

 

[PhatBob]

I've had a long chat with the local Audi dealer, they're replacing the servo and drying out the car at Audi's expense! Its called a goodwill repair or something similar...