1984 4k diff locking mechanism

[Bares, Vittorio]

Ok - so I've discovered that the 1984 version of the 4k has a subtly
different approach to the center diff locking mechanism. In later years
there is the typical vacuum actuator located in very close proximity to
each of the diff lock levers for center and rear diffs.

 

On the 84 however, they are both located on the rear diff. For the
center diff, there is a Bowden cable that is fixed solid from the rear
diff to the center diff. For those that don't know, a bownden cable is
very much like a bicycle brake cable, wire cable inside a plastic
sheath, where the cable can slide back and forth. The design on the Audi
is interesting in that the engineers decided that rather than moving the
cable inside the sheath, they would move the sheath its self, leaving
the cable fixed. The vacuum actuator moves a bracket that pushes the
cable sheath, and at the other end the sheath has a tab on it which acts
on the diff lever.

 

So now, my question - how much movement is required to engage the
differential lever? 

Do the diff levers (either front or rear) typically get 'stuck' from not
being used?

 

Thanks,

Vittorio -