[urq] Locking differentials

[QSHIPQ at aol.com]

This has been brought up before Dave.  I looked at this pretty intensely 
before going to the dual electro-pneumatic switch setup from the torsen rear 
lockers.  You can use a solenoid activation, which a couple folks have done.  I 
emailed one that had done this swap, and he indicated that it required a extra 
circuit board to 'rehit' the solenoids every xx seconds.  

I also looked at a separate vacuum activation from the cruise control pump, 
and decided that it's peak vacuum was too small.  I also explored using the 
Mercedes benz door lock actuators (quite beefy steel instead of plastic and dual 
chamber housings), but they aren't a direct swap.  I also explored copying the 
early urq design of the dual manual shifters by the ebrake.  After all this 
research, I found that the problems with the vacuum actuators are really the 
least of all evils.  Making sure you have good vacuum ck valves (I did two 
inline) as well as maybe addressing the CCV system, can assure good life of the 
stock valves.  The electro-pneumatic box setup with the switches sure seems more 
modern, and has worked flawlessly for the 2years since my install, even at 
7300ft Steamboat track.

Also a couple things regarding what's in your car.  The >83 urq's used a 
spring return on the dog clutch activation rod (where it exits the trans) and it 
was deleted on 84> quattros with lockers.  You can remove this spring in situ 
if you get another boot bellows.  Also, the bowden cable setup on the center 
diff kinda sucks (the rear stays the same on all quattros thru 95), and can be 
upgraded to the late style quattro rod activation (diaphram mounted above the 
PS driveshaft), which works much better than the NLA bowden cable setup.

Want to go really fancy?  Somewhere in the archives I give the procedure for 
swapping the dog clutch rod itself to upgrade to the late style (without the 
huge bowden anchor bracket) dog rod (it's a direct swap, albeit a PITA).

HTH

Scott Justusson
84 RS2URQ
83 URQ with dual E/P lockers
In a message dated 2/24/2004 4:44:10 PM Central Standard Time, 
bergeron at nwcomposites.com writes:
hello Y'all-
I am wondering if anyone has tested the locking differentials to see how
much force, in pounds or ounces, it takes to lock the center and rear
differentials.  Both of my vacuum actuators have failed and I think it is
time to come up with an "upgrade".  Thanks for your help,
Dave B.
83 Irk...oops, I mean URQ