2004 XLT, 2WD. Replaced right front wheel bearings and brake pads. Took it for a test drive. All was o.k. No noise, stopping is good. Did same work on left front. Test drive not good. When applying brakes during a stop, the ABS sensor comes on at any speed below 12 MPH. Always. Never an ABS dash light. The only difference between the two repairs is the second one received new caliper floating pins since one of the original pins was sticking. Could my repair cause this ABS function? If so, what do I look for?

 

Found post on YouTube concerning ABS problems under 10 MPH.

 

Did u disconnect the battery before collapsing the caliper?

 

Did u disconnect the battery before collapsing the caliper?

 

Disconnect battery? I have watched several videos and read post about doing the job before I started. I didn't see "disconnect the battery". How would that cause my ABS issue?

 

I replaced the LF ABS sensor ( with battery ground disconnected) and that did not resolve the issue. However, the ABS action is now more aggressive. That really does not make any sense. I expected either no change or solution but not more aggressive. Any ideas?

 

I really thought I had discovered the problem. I had over torqued the caliper sliding pins. So I corrected that to 24 ft. lbs. ABS is not as aggressive but still has fault activation. On a Hard stop, the ABS does not activate until speed reduces to 15 MPH. On slow rolling stops, ABS activates at 15 MPH.

 

Question: in the time from when u hit the brakes until u reach that 15mph or so, does anything else happen? Like anything with how the brake pedal feels? Sounds? Vibrations?

 

No, nothing usual and as before the repair. Thanks to an older post, I will be checking position of the exciter (tone) ring. Did I damage it during assembly? Hopefully will check tomorrow.

 

FINALLY! I discovered that I was not paying enough attention to the tone ring when I was driving the inside bearing race into position. I had moved the tone ring farther away from the ABS sensor. To correct this, first I established what the correct position of the tone ring should be. I measured the length of the sensor to the bottom of the mounting lug. ( it is part of the sensor.). My micrometer indicated 1.065". Based on a different post, the bottom of the sensor should clear the tone ring by .005" to .045". The correct position then from the tone ring to the sensor mounting position is 1.070" to 1.110". With the tire and caliper removed, I measured and marked the tone ring about each 4 inches around it's circumference. I used a different very small dot of paint on the tone ring to match the location with the measurement. This dot probably should be removed as the final step. Removal of the caliper made a short section of tone ring visible. That is where I used a flat screw driver to lift the ring back toward the sensor. I had to rotate and measure the tone ring 3 times to get it just right. If I over lifted a position, I was able to tap it back. My last step was to bolt the sensor in place and turn the rotor to make sure the sensor cleared the ring. You might not hear the contact, but you can feel it if you grip the sensor with two fingers while very slowly rotating the rotor.