I have a 2008 6.4 diesel with a hydraulic Clutch. The pedal does not return and stays half way down which is a sign the system has air in it. I bench bled the slave and master cylinder then pushed the slave cylinder back to get remaining air out of the line. I have tried every known technique to get the air out even held the master cylinder vertical while bench bleeding it and the results are always the same the pedal stays halfway down and I cannot get it into gear. Has anyone ever been successful in bleeding the system or is the only solution to buy another system. I did have a new one but it appeared to not have enough brake fluid in it. I fail to see how I cannot get all the air out. Any help will be greatly appreciated.

 

Does it have a Hydroboost system ? If so may be a problem there.

 

Could be a leak somewhere in the line. Maybe try pressurizing the system and see if you can spot any fluid escaping?