RE: one light on DIFFS

[Paul.Heneghan@bbc.co.uk]

My  1984 Audi 80 quattro has a peculiar problem with its diff locks.  
The rear diff is still ok, but If I lock the centre diff (with the 
pull-out vacuum operated switch in the centre console) and then try to 
unlock it again, it doesn't want to unlock (not good for tyre wear!).

When I first bought the car in 1990, it would unlock after 3 seconds or 
so of normal driving. Now the only way it can be unlocked is by 
suddenly taking the foot of the accelerator while driving at 6,000rpm 
in 2nd gear (ignoring the clouds of smoke) or driving in reverse.  This 
seems to jerk the diff out of lock.  I've never seen a Bentley manual 
in England, so I  have to work from a Haynes manual which doesn't cover 
my particular model.

Thanks to Paul Timmerman and Robert D. Houk for the articles they've 
posted on diff lock actuators.  I'll have a look at mine and see if I 
can sort out the problem.

Now the questions!

1)  I see a lot of reference to a Bentley manual - I haven't ever seen 
one in England, so I'm stuck with the Haynes.  Does Bentley cover the 
quattro models?
2)  Does anyone have an ISBN and an approximate price for a Bentley 
manual for a 1984 Audi 80 quattro 2144cc K-Jetronic (similar to 4000CSQ?)?
3)  How easy is it to repair a small leak (from the case seal?) on the 
rear diff?

Sorry for the long message. Thanks for reading it

Paul Heneghan

1984 Audi 80 quattro (130k)
1983 Audi 100 CD Avant Auto (124k)
1980 VW Jetta GLi (135k) rusting in the garden - any kit cars use these 
mechanics?