Anti lock brake question

Yes i have a problem with my anti lock brakes. They keep engaging at low speed when braking just b-4 i stop. I already changed the rotors and brake pads in the front thinking it was a warped rotor. Now i think its either a wheel speed sensor or electrical , be cause when i unpluged the anti locks under the hood it stopped. But it is my wifes everyday driver and she needs he speedo to work. Does anyone know what to do? I cleaned off the sensors in the front. Do you think its a fuse ? Any help would be really appreciated. Its a 2000 explorer xlt 4x4 4.0. Pleese someone help me

come on people! help me out

Bump up

"keep engaging at low speed when braking just b-4 i stop. "
Every time i stopped the ABS would kick in for the last 5 feet or so, No ABS light, there wasn't any ABS codes either, it was working fine according to the scan tool. On a jeep there are four sensors and tone rings that you can easily inspect. It sounded like the tone rings where dirty. On my jeep this turned out to be a parking brake clip which pulled out and covered the sensor inside the brakes. other than that is to try and inspect all of the sensors and tone rings for cracks but its a PIA.

my bad i thought this was for a 3rd gen . . this applies to an '04 Ex - which was a little different and more complex than a jeep, but if you have RSC there should be two rear sensors that you can actually see it might be them. Otherwise non-RSC there is a sensor on the diff, but again its really hard to see and you have to pull it apart to see the tone ring, the fronts are in the hub with the tone rings are inside the bearing.

Hopefully the ABS light on?
Just to start you off:

If you do have a light the Best thing and cheapest is to have someone read the ABS code. It will help a lot as there are about 9-11 sensors that can go bad: ABS module, Brake Pressure Transducer, L/R Front wheel sensors, Brake Travel sensor, rear wheel sensor(s), accelerometer, steering wheel rotation, traction control switch. The most common ones are the Rear diff sensor, and if you have it the master cylinder switch, and then the fronts bearings.

Check the front wheel bearings. A bad/ loose wheel bearing (hub assembly) can cause the tone ring to wiggle at slow speeds which confuses the ABS and causes it to engage.

Thanks guys i'll see what i come up with. Any other advice?

Bump!!

Come on guys, does anyone know how to fix this? Or help me out

Without connecting a scanner to view the inputs and outputs of the system, there's simply no way to know exactly what's causing the system to detect an ABS event. It's impossible to know.

Now, that being said, the most common cause, in my experience on this forum, is an ABS sensor that's dropping out the signal prematurely as you come to a stop. This can be caused by bad hubs on a 4x4, loose bearings on a 2wd, or issues related to the rear axle speed sensor on the rear diff. The most common of the three possible ares is the sensor on the rear diff. Replacing it fixes this sort of problem about 3/4 of the time on here. As we start to see more and more of these failures as these vehicles age, it's getting to be more and more common. It's a $15 part, takes 20 minutes to change, and might cure it. If it doesn't, you're only out $15 and 20 minutes.

I'm not saying it'll fix your problem, because I don't know. But it can't hurt to try.

-Joe

gijoecam said:

without connecting a scanner to view the inputs and outputs of the system, there's simply no way to know exactly what's causing the system to detect an abs event. It's impossible to know.

Now, that being said, the most common cause, in my experience on this forum, is an abs sensor that's dropping out the signal prematurely as you come to a stop. This can be caused by bad hubs on a 4x4, loose bearings on a 2wd, or issues related to the rear axle speed sensor on the rear diff. The most common of the three possible ares is the sensor on the rear diff. Replacing it fixes this sort of problem about 3/4 of the time on here. As we start to see more and more of these failures as these vehicles age, it's getting to be more and more common. It's a $15 part, takes 20 minutes to change, and might cure it. If it doesn't, you're only out $15 and 20 minutes.

I'm not saying it'll fix your problem, because i don't know. But it can't hurt to try.

-joe

Click to expand...

thanks bro, so you say the weel speed sensor is on the diff? What is the sensor attached to the hub? I was under the impression that was it. But maybe thats the reason its still doing it! Thanks again, i'll keep ya posted

There are three: One at each front wheel hub assembly, and one on the rear differential. Any of the three could be causing the problem, but like I said, the rear is the most common... It's a little more exposed than the front two, leaving it more vulnerable. It's also the cheapest of the three as well.

gijoecam said:

there are three: One at each front wheel hub assembly, and one on the rear differential. Any of the three could be causing the problem, but like i said, the rear is the most common... It's a little more exposed than the front two, leaving it more vulnerable. It's also the cheapest of the three as well.

Click to expand...

do you think it just needs to be replaced? Or can it just be cleaned?

DIRT ROAD said:

do you think it just needs to be replaced? Or can it just be cleaned?

Click to expand...

Depends what it looks like when you take the old one out... But for $15, I wouldn't want to go through the effort of removing it just to put one back in that might be bad...

just be warned...do not dent the tone ring....like I did...or your abs will not function correctly

took me a while to figure that one out

Im having the exact same issue. A few days ago my ABS light did come on while I was driving home and stayed on until I shut the truck off. While the light was on my brakes acted normal (ABS didnt engage). The light hasnt come on in a few days. Today I got home and put into park and shut it off. I got out and shut my door. All of a sudden I heard a dull clicking and noticed my truck was rolling backward. I reparked and applied the parking brake.

Somewhere online I read that the brake booster might be bad. Not sure if any of these events are related but it'd be nice to know where to start.

Had the same issue with mine, since it showed up after suspension and brake change, figured I got air in lines, bled whole system including ABS still doing it, finally took a test drive with scanner hooked up and found the front R wheel sensor was dropping out when speed got below 9mph, just went t 0. Replaced the sensor and working fine now. How you can tell which sensor is feel which way it pulls when coming to a stop, my truck would pull to the left at a stop. Good luc