I have a 2004 Fiesta Tdci that has gone very well for 60,000 miles. Recently I experienced a concern when operating the clutch-but only intermittently. When pressing the pedal a crack is heard as if the cable has snapped. However as it is an hydraulic clutch this cannot be. The pedal goes straight to the floorboards but when you take your foot off the pedal the pedal recovers and allows the pedal to be depressed again-this time the clutch works normally. It happens about once a week-sometimes when moving off from rest, sometimes when changing gear. There is no fluid loss, the level in the reservoir does not go down -and the clutch has never been replaced. My local servicing garage and I are at a loss to determine the cause- we fitted a small clip last time to the operating arm where it goes into the master cylinder-in theory it cannot happen but it does-HELP?