1984 4k diff locking mechanism

dgraber460 at aol.com dgraber460 at aol.com
Thu Nov 13 11:50:05 PST 2008

Are you asking about the movement required for the front diff or the rear?
I have both out of a car?from which I can get a measurement for you.
Last year I tried to make a manual set up to engage both front and rear independently. I found out why the engineers built it that way they did. The control wire from the center of a?Bouden cable flexes and bends before it engages the diff. I used heavy duty cables from big rig suppliers (not the Checker/Flaps choke cable type) and it would not provide enough push/pull to work the diffs.
I'm still wanting to fab something to give independent and manual control.

Dennis Graber
Denver, CO

-----Original Message-----
From: Bares, Vittorio <Vittorio.Bares at nuance.com>
To: quattro at audifans.com
Sent: Thu, 13 Nov 2008 11:58 am
Subject: 1984 4k diff locking mechanism

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?



Vittorio -


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