I think I know what 5-Channel ABS refers to. I think some (maybe all?)
ABS pumps have 2 output lines each for each of the front wheels, and a
single line for both rear calipers. In my 911, that was the way it
worked - at least.
Mike Lawton
'86 4ksq
'90 Carrera 2 Targa
'96 Triumph Sprint