Couple of things could be at play here. One, the sensors don't sound right - they should have been direct replacements - no modifications required - and the washers you have used have possibly set an incorrect airgap on the sensors.
And two, the front wheel bearing has the "tone ring" (reluctor wheel) built into it, usually only on one side, so if it is installed backwards, the wheel speed sensor has nothing to detect.
The side with the chamfer must point inwards (towards the centre of the car).
