I just put a new speed sensor in the rear diff (9.75" with 3.55 and an Auburn Gear L/S) because my ABS light was on in the dash panel. Now under moderately hard braking it feels like the ABS is kicking in, and it shouldn't be. The light is off now, too. Does it just take a while for the ABS computer to "adapt" to the new sensor? Also, I didn't siconnect the battery when I did it... IT is illegal to work on your vehicle while it is parked on the road, even right in front of your house, here in Germany(yuck), So I crwled under there last night and threw the sensor in as quick as possible. would disconnecting the battery rest anything? Am I worrying over nothing?

 

I think so...if the light is off, your ABS is working.

 

There is no adjustment period. There is no need to disconnect the battery.

If you're getting improper (premature or erratic) ABS activation, you've got a new problem.

What year and is it 2- or 4-wheel ABS? Stock size tires or oversize? Any other drivetrain mods?

Steve

 

It's a 2000 4 wheel drive, with 275-70 tires(slightly larger than stock) and an Auburn gear Limited Slip. Like I said, the braking system seamed to work fine when the light was on, and I just put in a new sensor. After driving the truck more yesterday, it feels like the brakes are locking up all the time, it's just more noticable when I'm coming to a stop...ie I get that ABS chatter on the pedal right before I stop. I'm thinking of puting the old sensor back in... If the light is on, at least the brakes worked correctly.

 

well, I put the old densor back in and the light came back on, but no more ABS kicking in too early. But now, maybe I'm just imagining things, but it feels sluggish and slows down faster than I remember when coasting, like maybe the brakes are slightly dragging? gggrrrr... I'm going to take it to the Ford dealer here (I'm in germany, remember...)They do some work on government trucks, and was told they MIGHT have an ABS reader.

 

If you have RABS, you can pull the codes yourself. That's why I asked.

Remember, if the ABS light is ON, the ABS is TURNED OFF any you're just using standard hyraulic/power brakes. That's why, with the old, faulty sensor installed, you're not getting any premature ABS activation (it is turned OFF).

Part of the differential is an exciter tone ring that the ABS sensor sits immediately next to. The rear ABS sensor has to be in the correct relationship to the tone ring in order to get a proper signal to send to the ABS module. If the exciter ring is misaligned, cracked, missing, etc, the sensor will not be able generate the correct signal and will cause erratic symptoms, perhaps including those you are seeing. Perhaps there is an issue with the Auburn or its installation.

If you have 4WABS, there are two additional sensors, each mounted on one of the front wheel spindles that monitor the rotation of each on those wheels. The exciter ring on the fronts is usually part of the wheel hub and is susceptible to cracking and distortion causing a faulty sensor reading. Addditionally, these sensors can be faulty and cause problems.

If you do happen to have a brake dragging, you will find one corner where the hub is very hot compared to the others after driving. Perhaps even a heavier film of brake dust. Something to look for.

Steve

 

I had driven the truck around for 1,000+ miles without the light on, or any other brake problems immediately after the installation of the new ring/pinion/ Auburn L/S. If the front sensors were bad, wouldn't the light stay on with the new sensor in the rear? Can the ring/pinion be installed without the exciter ring? I thought that was part of the actual pumpkin...? Hopefully I'll get some answers tomorrow...I'm kinda thinking ABS pump or bad valve?Some sort of actuator? Thanks.

 

If you want help, it really is a good idea to ANSWER THE QUESTIONS....

 

answer what questions? Sorry, I landed on my head one too many time after jumping out of an airplane.

 

RABS or 4WABS...

Danged airborne..... And I bet it was a perfectly good airplane...

Steve

 

Must be 4wabs... has the sensors on the front too... And they were all pefectly good planes! lol