RE: Locking Brakes on Quattros?

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> I picked up that pulling e-brake turns can damage the quattro drive train.
> 
... is that right?  I don't think so.  By definition, every time you are
running in anything other than a straight line, each of the four wheels
covers a different distance!  I doubt that there are too many quattros
driven in only a straight line!  Differentials are meant to make up the
differences in rotation rates between the two sides ... I suppose that when
there is a difference in relative speeds the gears inside the differential
move relative to each other, but in my mind this should only be a good
thing.  If there was no differential motion at all I would imagine that you
could get wear only on parts of the gears, while motion should cause fairly
even wear ...

> If that is true, I assume that having less than all four wheels lock at
> the
> excact same moment will cause the same type of damage? It's not like I
> ever
> lock 'em up on purpose but I'd like to know if anything bad(besides tire
> damage) is happening when they do lock.
> 
Certainly for the short relative period that you would have the wheels
locked as compared to the total amount of time that they are running at
similar speeds I can't possibly imagine any damage at all being done ...

Steve Buchholz
San Jose, CA (USA)

With an '87 5kCSQ into which someone installed a tranny from a non-turbo ...
given the 4.11:1 front FDR and the 3.89:1 rear FDR ... that center diff is
working all the time!  No apparent problems (with the tranny that is!)