We have a Diesel Ford Fiesta (Mk4) - manual transmission, and its clutch pedal is very hard to push after a short drive. I.e. in the morning it's ok, but later it becomes very hard to push. I'm no mechanic, but it sounds like a problem with the hydraulics (right?).
Anyone has any ideas as to why this happens and what can I do to fix it? The car has had 170000km, and as far as I understand, it has a hydraulic pump to aid with the pushing of the clutch.