Whilst taking my audi tt for a drive I noticed straight away that the brake pedal was hard and not braking well at all, I assumed it was just because I hadn't used it in a few months. However the problem didn't go away after driving for a few minutes. The issue was in fact a brake in the vacuum line. This is situated near the firewall and just below where you put brake fuild in. Check this and make sure that there are no cracks before moving on to any other potential issue
