Recently I have notice the clutch on my 2.0tdi seems to be bait harsh and it feels as tho the biting point is changing slightly. One minute it's nice and smooth pulling away the next minute you move the pedal a mm and the car violently lurches forward as the clutch engages. Is this possibly the master cylinder? And how hard are they to change? I've bled the clutch system twice myself and payed a garage to do it aswel just to make sure after my attempts seemed to fail. But still no difference. HELP!!!!!!