[V8] bad bomb, master cylinder or ?

[Mark Kalbskopf]

I have the exact same symptoms you describe with the brake being hard  
at the top of the pedal and then sinking down 2 inches before it  
engages.
It happens usually after the car is first started and for the first  
couple of brake pushes.
I replaced the brake master cylinder, and it had no affect whatsoever!!
It almost appears to be ABS related, because I think I can hear the  
ABS engaging with that grinding pulsing noise very, very slightly on  
the first trip down my driveway in the morning.
My bomb was replaced about 12,000 miles ago.

I also have the differential locking up at slow speed issue, with the  
'ABS-Off' light coming on sporadically but I'm not sure if they're  
related.  I have replaced one ABS sensor, (the one with the higher  
resistance, with also absolutely no affect.

Maybe if I replace the whole car, it will have an affect!!!  :)

mark.