No brakes !!!!!!!!!

[Vitesse39]

I have a 93 530i V8 E34

The brakes work fine - very well in fact normally and passed MOT not so long ago.

But, when you do an emergency stop if you put your foot down too quickly the pedal shoots down abit, goes solid and gives very little braking then begins to brake again.
If you manage to start to apply the brake very and I mean very softly then build up they will stop, but by that time you have spent way to long in starting to stop (if you see what I mean).

I'm training to become an instructor at the moment so I know i'm not stabbing at it or that it's my fault and there isn't the usual judder associated with the ABS coming in - anyone got any ideas ?