Master Cylinder and ABS

[JJK1204@aol.com]

Hi all,
I sent this once but have not seen it in the last digests, so if it is a 
duplicate please accept my apologies ...

I would appreciate some help on diagnosing the master cylinder on my 87 5ktq. 
First, I know that the bomb is bad, 1 pump and the pedal is hard. Engine 
running I can slowly, or quickly, depress the pedal all the way to the floor 
where I get the brake warning signal. The pads and rotors are new and the 
calipers are fine, I bled the system and the brake hoses look in good 
condition. Normally I would suspect a worn master cylinder but it is 
difficult for me to confirm this with the hydraulic booster. Are there any 
signs I should look for, or am I just seeing the bad bomb effects?

As I have said, the pads and rotors are new as are the front wheel bearings. 
I bought new ABS sensor caps and installed them on all four sensors. The ABS 
light is off on startup but comes on as soon as I start moving and exceed the 
4 mph threshold speed. If I stop and recycle the light with the ABS switch it 
does the same thing as a cold start. Is there anything other than a bad 
sensor that could cause this behavior? Also, since I don't have a scope is 
there another good way to check the sensors?

TIA,
John Katos

87 5KTQ
Many Alfas