help me find my ABS pump problem

[Grifter]

i'm trying to diagnose a problem on my 97... when i take the car out of park and begine to move, the ABS pump cycles like mad.. constant cycling. not like an ABS pulse, but a steady cycle.. if i touch the brake pedal, it stops cycling. if i use the brake enough to stop the car the ABS pump cycles like it would under a panic stop situation. when i let off the brake again and begien to move, it starts all over with the steady cycle.. when i am trying to stop the car, the pedal feels very soft and has a very low engagement point, maybe 1" - 2" off the floor..
thats what prompted my asking about tire sizes, because i was thinking it might be related to a speed sensor or something. is there anything i could have screwed up while doing the hubswap that would have caused this? the rear speed sensors are on the pumpkin, so those arent touched. the fronts are run off the new hubs, mounted on the spindle, so that should be ok, i didnt have to touch the sensors.

anyone else ever have this problem?

 

[chicken]

if there is the smallest difference in the front excitor rings it will go to hell in a handbasket take the hubs off and count the "peaks" make sure its the same size around they have to be EXACT or it wont work at all you might want to check out tccoa.com a lot of t-bird'ers are swapping to the mustang hubs so id see if anyone else has had the same prob

 

[Frat-man-du]

Any chance it is the Air pump?

Nevermind I read further. Since the front is the only change you made I would think the excitor rings dont match. Do you get the warning lamp?

 

[Grifter]

no, no warning lamp.
the air pump isnt hooked up normally, i did the kale mod, so its controlled by switches.. only runs when i tell it to.

i'm thinking that maybe thats the thing, maybe i got a funky exciter ring or maybe somehow a wheel sensor crapped out..