Brake pedal sometimes sinks to floor

[LewisW2105]

Hi guys, I've got an Audi A1 2011 1.6L TDI. I've noticed in the last few months that sometimes when I'm applying the brake pedal at low-medium speeds the pedal just sinks straight to the floor with very little brake effect (but there is some when it reaches the floor) if I lift my foot off the brake pedal and reapply it works perfectly. I don't really know where to start with this one, I've seen on other threads with people with similar problems mention the master cylinder. Any help would be appreciated. Thanks, Lewis.

[philipharmes]

If your not loosing any brake fluid, it will almost certainly require a new master cylinder.

Some you can get new seals fitted, but newer cars tend need a complete new MC as replacement seals are not available.

[Crasher]

That is an extremely unusual failure and considering it is used right across the group in the Polo (hence the 6R prefix for the part number), Ibiza, Toledo, Fabia and Roomster if it was common there would be technical product information notices about it. I would have the master cylinder replaced as a precaution. It is right hand drive specific and the VAG number is 6R2 611 019 B REP which is £223, it was originally made by ATE and at the moment is not available aftermarket from what I can see.

[LewisW2105]

Its 2011 I don’t know if that counts as a new car. But thanks I’ll look into getting it replaced