Just over 40ml, or 1.4 fl oz, remains in old fluid in the Modulator/Pump Assembly and having the engine running doesn't push it out either.
To operate the valves in the modulator, it needs to detect a fault, so by spinning the wheel connected to the circuit you are bleeding with the ignition turned on may be seen as a fault in that circuit on the 600 which if I remember correctly is a WABCO system.
This isn't the case on the R40 where the ABS ECU will see the other three wheels as being static and do nothing
Brian
