Ford Repair: ABS engaging at slow speeds NO light, dry pavement, air gap

Question
1999 Grand Marquis w/traction control.After replacing the right rear axle(brand new with proper sensor ring),bearing and seal after oil leakage the ABS system is engaging all the time at slower speeds and when comming to a stop.The ABS motor is "hammering" the brakes wich would be normal on icy roads but it does it on dry pavement but not at freewayspeed.So because the ABS sensor had gotten a lot of gear oil on it I replaced it with a new sensor.Everything is nice and clean and I also put on new rear brake pads & new parking brake shoes wich had gotten oily as well.The result is still the same and there is no warning light displayed.The warning light works because after getting tired of the constant brake hammering I disconnected one rear ABS sensor under the rear seat wich turns on the ABS light and traction control light and disables ABS altogether.I can't figure out what else to try,nothing else was changed except for the axle as described above.

Answer
Hi Stefan,
It sounds like you might have the wrong axle or the ABS ring is dented or damaged. Also check and see if the number of teeth on the ring you replaced and the one on the other axle. They must be the same. Also check the gap between the sensor and the ring (called air gap)on on side and the one you replaced. That must be the same also. No dents or dings on any of the 4 ABS rings. Make sure all 4 ABS sensors are tight.
If one ring has more teeth or the air gap is too big then the ABS system thinks that one wheel is moving faster than the other and sets the ABS system to operate. Thats the hammering you feel. It's the ABS pump motor working. If you need an easy way to disconnect the ABS system, just remove the ABS fuze from the box and put it back in to retest the system. GOOD LUCK!!

Jeff
AllExperts