vacuum hubs

I have changed a front wheel bearing and while the 4wd drive worked it stopped soon after, I put this down to a blocked pipe due to grease, stripped and cleaned but what I found was that it would go into 4x4 cams sliding onto drive shaft it would not come off. I have blown into the pipe at the top of the hub and their is an air leak. I have taken the hub apart again and put in a new oil seal but it is still leaking air. what i cant find out is what is the vacuum path in the hub. it looks like to enter 4 wd the vacuum is aplied via the drive shaft but what is the path to take it out of 4x4.

Air leak solved, I had missed the bit in the manual about filling the recess between the outside of the hub and the shield with 60% grease, (it seemed wrong at the time to put grease outside the oil seal what do i know).
However the 4x4 stopped working once the car moved. 4x4 light solid green on the dash. any ideas?

Are the two pipes in the correct order?

Mark

The vacuum to engage goes along the cv joint splines and inside the hub through the middle of the outer oilseal. The air that goes in to do the engaging goes through the bearing rollers and goes outside the outer oil seal, there are air holes in the black hub outboard of the seal. (shaded in grey)

The vacuum to disengage goes on the outside (and needs the inner wheelbearing seal to be tight to work), air has to get in through the hub centre along the CV splines.

If either spigot is blocked up it will not work.(because air has to get in to push the other side, the vacuum removes the air from one side)
With the black hub removed you must be able to blow easily through both spigots.

If the wheelbearing seal on the inside of the bearing leaks the hub will not disengage.
If the innermost seal that runs on the CV joint leaks, it will not engage.
If the outer seal (against the lip on the hub "nut") leaks the hub wont move either way.