soft brake pedal?

[CharlesP]

on my 2006, B6, Sport, the brakes have been getting progressively worse over past year. Now, pressing the brake pedal down gives a little bite and then it goes very soft until it close to the floor and going hard. The car is now at VAGTune in Aylesbury and they have bled the brakes several times in past month and do not get any air out. Neither does the biting point come up away from the floor. They have also exercised the ABS but still brakes only bite close to floor. I predicted this was a master cylinder issue but they have not checked that yet. I also feel that he brake servo is not assisting the braking force. All callipers and hoses are in good condition and there's no loss of fluid level or leaks from any of the circuit..
Does anyone have any experience of symptoms like this?

[acattanach]

Bulging Brake pipes?

[micheal balbrig]

Any brake imbalance showing on brake test ?.

[RichardSEL]

Lack of servo assist would mean your pedal being hard from the top of its travel and not providing any, or very little braking unless pressed very hard.

You're right to suspect master cylinder.

Also has the fluid been changed? It could've gone hydroscopic. Although that usually shows, like air in the system, as a need to pump the brake pedal to get braking. If changed or topped up was this done with the correct fluid? Although people do use DOT4, better to get the correct VW spec stuff

How's your fluid reservoir level?

If there's no leeching of brake fluid seen seen then you'll have to change master cylinder to eliminate.