Source of O-rings for rebuilding brakes

[radek at istar.ca]

Hello fellow Audifans.

I took apart the leaking rear brake caliper on my Typ 89.  It was leaking from the e-brake
shaft, the piston
itself is OK.  Now I have to replace an O-ring, about the diameter of a quarter, that goes
on the e-brake activator
shaft deep inside the caliper and seals the main brake chamber from the dry e-brake part.
Local hydraulic
equipment shops tell me the O-ring has to be made of special rubber, ethylene propylene or
E-540, which they
don't have.  Regular O-rings would swell and break down when immersed in brake fluid, they
say.

Would anyone know where to look for such O-rings?  Local automotive shops are no help, of
course.
The "caliper rebuild kit", part 443 698 671, only has the rubber boot and the large O-ring
that goes around
the piston.  I don't need these.

The other question I have is how to remove the e-brake shaft?  It only goes out a small
distance
and gets stuck.  Is there anything holding it that I don't see?  I dont't want to force it
unless I have to.

Thanks to all.

Radek
88 90Q
91 V8Q 5-sp