Ur-quattro brake question

[quk@sievers.com (Phil Payne)]

In message <9610241802.AA08274@vtkapp.voicetek.com> Bryan Gunn writes:

> For those of you in the UK ans elsewhere, did Audi change the brake servo
> and/or hydraulic pump when they installed the dual piston calipers in '87?

I have communed with the German parts microfiche - this is what I gleaned:

   857 611 019               -> 85-C-901031
   443 611 021   85-C-901032 -> 85-H-900550* 23,81x19/17
   447 611 021   85-H-900561 ->              25,40x18/18
 
OK.  The parts fiche only illustrates the one-pot caliper, clearly identifying 
it.  But it lists another underneath it, using the convention of putting the 
number in brackets (1) to indicate an unillustrated part.  This change occurs 
at Fahrgestellnummer 85-H-900001.  My guess is that this is the twin-pot change.

My reading is that the switch to twin-pot calipers occured _before_ the switch 
to 25mm master cylinders - 85-H-900001 to 85-H-00550 would have twin-pot 
calipers but 23mm master cylinders.

YMMV.

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club