Clutch Does Not Release
 

I have a 2008 Ford F250 before I overhauled the 6.4 diesel engine I had trouble getting it into gear. After overhaul the pedal stays down halfway and cannot get it into gear. This is a classic sign there is air in the hydraulic clutch system. However, I am certain I got all the air out, even bought two aftermarket systems and same problem, pedal stays halfway down. I have taken the transmission out and can find nothing wrong with fork, the plastic wedge or throughout bearing. I read in the book that the flywheel and pressure plate must be put in a press to adjust the ring till the springs are compressed. I do not know what this does and don't believe it will fix my issue. Did anyone every have the same problem and what did you do to remedy this issue? Any help would be appreciated I want to drive it

Not sure what is really going on.
A heavy duty clutch does have an adjusting ring.where the pedal must be in the fully down position and either held there with a person's foot or blocked there with something BEFORE THE ADJUSTING RING CAN BE ADJUSTED.

There should be no kind of plastic wedge.with this system. Did you replace the clutch pressure plate and clutch disc ?
Some clutch pressure plates come with wedges to hold clutch in released position , but need to be removed upon installation.
Need more details of EXACTLY WHAT YOU DID.

The person I bought the truck from had someone install a disc and pressure plate. I had a hard time getting it into gear then. I could only get it in first or reverse and the truck would creep along with pedal to the floor. I O/hauled the engine and re-installed the disc and pressure plate. Pedal stays halfway to the floor as aforementioned I put in two aftermarket systems and had same problem.. The book says that I must put the flywheel and pressure plate in a press to adjust clutch it does not say to install the disc. I adjusted the ring till there was tension on the springs held it there and released the pressure on the pressure plate. I then re-installed the disc and pressure plate. I have not installed the transmission. What does this ring do? Could it remedy my problem?

Attached 3 pdf files for 07 F-250 6.0L for your reference.

There is a right way and a wrong way to install a clutch disc.
You will notice the disc has a hub that protrudes (sticks out) on one side.
That part of the disc must go toward the pressure plate If it was installed backwards you can wind up with the problem you have.
You need the alignment tool to align the interior splines of the disc with the pilot bearing so the splines on the trans input shaft will slide through the disc all the way in.
There may be an X on the flywheel that should align with an X on the pressure plate assy to assure better balancing of the entire assy.

Please get back to me , I should be able to save you a lot of unnecessary work.
In reading your last post I suspect the disc was installed backwards. This will result with the disc hub up against the flywheel preventing full pressure of the disc against the flywheel and also not allow the input shaft to stop so you can get it into gear.