I've got a Honda Civic 1.8 EX - 2006 - 85000 miles on original clutch. The clutch doesn't slip and has adaquate pressure during normal driving (0-40 mph) however as soon as I get on the motorway (50-70 mph) the clutch pedal becomes very soft. So soft that I can push it down with my little finger. It still changes gears albeit the biting point is very low! The pedal does come back up but light as a feather going down. Sometimes the gear changes are very abrupt, even when letting the clutch out slowly - mainly on cold, damp days at any speed. In 1st gear, if I accelerate to 10 mph then let the car slow down to 8 mph, the car will suddenly jerk like I've hit something.
I've scoured though days if not weeks going over various forums and speaking to different mechanics to no avail.
I've tried: Flushing the clutch fluid multiple times, even got a garage to do it. Adjusting the CMC (behind pedal) Checked for any leaks in CMC and CSC No fluid loss at all - fluid light brown colour.