ABS chatter

[gordy.schesel]

One of my 91 quattros is having ABS chatter when braking to a stop on dry
pavement.  Odometer has 240k miles.  Is the problem corrosion of one or more
wheel sensors?  I have had two different non-dealer Audi techs work on the
problem, but they were unsuccessful.  How hard could it be?  What can I do
for my own diagnosis?  Use a continuity test, or A/C volts test?  The
Bentley refers to the dealer's tester and procedures only.

 

If the problem is corrosion, then what?  Can I just disable the ABS?  Is it
done by pulling the combination ABS relay (#8) on the auxilliary relay
panel?

 

TIA

 

Gordy in St Paul