I would recommend bleeding the lines again before you get too worried. When I installed mine, I thought that I had it all bled and when I first tried it I couldn't get it in gear - I then said some choice words since I didn't want to take it all apart again. Then I decided to bleed it again and as soon as I cracked the bleeder it let a bunch of air out and then worked fine.
I can't speak as to the external slave, but the internal doesn't have any sort of an "adjustment shaft." I agree with UglySkunk; I would replace both the master and the slave (especially since yours is external) since if one goes the other is probably close behind.
Hopefully it is the master and slave and not something to do the throwout bearing, clutch fork, clutch disk, pressure plate, ect. HTH and good luck!
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92 Canyon Blue Wrangler YJ 4.0L - with some fun goodies