just replaced the clutch master cyl on my 74 B have bled the system until there does not appear to be any air in it. and now cannot get enough pressure to allow me to shift gears. All was working fine before I replaced the unit the old one was merely leaking.

You still have air. The clutch hydraulics are very hard to get air free.

I went through the same thing and went through a quart and a half of fluid trying to get all the air out. I was using a ez bleeder and every time I would think it was air free a few more bubbles would come out.

Drain the clutch master. Pump fluid in from the cyl. bleed valve. Works for me. It seems to push the air up through the master cyl. Constantly check the reservoir so it doesn't overflow. JMHO. PJ

Thanks for the response looks like I just need to keep pumping until the air is removed.
The idea of pumping fluid back through the bleed valve is interesting but do not know how you do that.

Just incase is the bleeder facing forward on the slave or pointed toward the side of the car? If its pointed forward you need swap the hose and the bleeder and any trapped air should come right out.

Indeed; dunno why but they supply the slave with the bleeder fitted into the wrong drilling. My clutch hose was stretched to a weird angle. Swapped them around and it bled just fine.

It doesn't fit in the box if they put it in the correct hole to begin with. I guess they decided to do it that way instead of getting a bigger box, or leaving the nipple loose in the box.