Pug,
It sounds like you have an actuation problem. It is most likely that it is a hydraulic problem. The initial operation should be a thorough and successful bleeding job. We've found the adjustable pushrod to be of no great use. First, the system is "hydrostatic". That means that the piston in the slave cylinder comes to rest upon complete clutch release wherever in the bore that the clutch springs leave it. No "bottoming" is intended. The piston sits there AGAINST the pushrod, waiting for pressure from the master cylinder, at which time it instantly begins its movement toward releasing the clutch. Installing the adjustable pushrod merely positions the slave piston in a different place in the slave bore. Another thing we've seen is that someone who perhaps doesn't know the nature of the system will install a return spring on the slave cylinder. This is working against one's self, as can be seen considering the way a hydrostatic system is supposed to work. There is one situation where folks use the adjustable pushrod, thinking that they've solved the problem. They have not. It'll come back in spades eventually.
If the clutch linkage that's internal to the bellhousing is in trouble, the arm that comes out to connect to the pushrod may have taken up a position with its holes (Three; the bottom hole gives the most movement per inch of pedal travel). well back from where it should be. At rest, the arm (lever) should be vertical or just foreward (towards the front) of vertical. If yours is significantly angled to the rear, you probably have the typical throwout fork broken set screw where it fastens to the cross shaft. This also can account for a very stiff pedal. Some install the adjustable rod (ALWAYS adjusted to be longer than the original) because the travel and positioning of the piston without it would cause the slave to traveel all the way to the rear. Even if this doesn't spill fluid, the crud in the end of the slave bore may lift the cup of the piston and allow air in. If the arm is as described, you'll need to pull the gearbox and replace the cross shaft, fork, screw, and perhaps the cross shaft bushings. While you're in there, check the clutch itself and consider a new release bearing.
Let us know what you find upon diagnosis.
Motorbill
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon