This thread will tell how to replace a front ABS wheel speed sensor on a 2000 ranger 4x4.
Indications: Generally, indication of a front wheel speed sensor failure will reveal itself at low speeds, usually somewhere below 6mph when you are coming to a stop. The abs for the faulty sensor will send a signal to the ABS to initiate. when this happens, you will feel the abs kick in and will feel the truck pull to one side or the other. what is happening is that the good speed sensor doesn't kick and so that side wants to stop normally, while the faulty side will cause the ABS to pulse. The way to know which abs sensor is bad is to determine which direction the truck pulls when this condition happens. If it pulls to the right, the left (driver) side sensor is bad, if it pulls to the left, the right (passenger) side sensor is bad.

So, if this condition exists, it is time to replace that faulty sensor. The first thing you will need to do is purchase a new ABS front wheel speed sensor. For my truck, the best deal i found on the sensor itself was a Dorman product 970-022 that i purchased on amazon.com for $55 delivered. Places like Advance Auto Parts, Oreilly, etc, were all 3 or 4 times that cost just for the sensor. Make sure you order the correct part; if you want the Dorman part, you can go to Dorman Products and find the correct one. Like i say, this was the Dorman product that worked for my truck.

Here are the steps:
1. Safely jack the truck up and place appropriate stands to make working on the truck safe.
2. Remove front wheel on the side that you determined has the faulty sensor
3. Remove the two bolts holding the brake caliper frame on, not the caliper pins, but the bolts holding the caliper frame. They are 15mm bolts that are access on the back side of the caliper frame.
4. once those two bolts are removed, you should be able to pull the rotor off with brake caliper still attached. have a bucket sitting upside down next to you to be able to rest this rotor/caliper on while you work
5. remove 3 dust shield bolts, 5/16". This will expose the wheel speed sensor, which is held in place by a 5mm allen head bolt.
6. Remove any excess corrosion/debris from around the sensor and connector.
7. Disconnect the sensor harness from the sensor
8. Remove the 5mm allen head mounting bolt that secures the sensor to the hub
9. Carefully try to remove the sensor. This can be a tricky thing, because many times, the sensor will finish coming apart when you pull it. Mine left the plastic housing inside the hub. I had a vacuum handy that allowed me to clean around the sensor hole and help keep stuff from going inside the sensor ring area. Make sure junk doesnt go down that hole! that vacuum will help that. if the sensor comes apart leaving plastic in the hole, use tweezers, picks, whatever you can to help get it out and keep that vacuum running the hole time to help keep junk out of the hole. I used a 5/16" drill bit turning clockwise very slowly (dont forget to have that vacuum going). this helped to remove those internals a little bit at a time. I was able to eventually use my hemostats to grab it and pull it free from the hole.
10. once the old one and any leftover parts has been removed (inspect closely to make sure nothing is left), i got some steel wool to try to clean the inside of that hole as good as i could, with that vacuum running.
11. once cleaned, apply a light film of lubricant (supplied with the part, or use vaseline) around the seal / o-ring on the new sensor
12. Install the new sensor to the vehicle using the 5mm allen head mounting bolt that secures the sensor to the hub. You may need to force the new sensor into the hole, but i wouldnt force too hard. if it doesnt want to go in, get that steel wool and vacuum out again and try to clean the hole up a little more. then try again, dont forget the lubricant. you may need to tap it very lightly with a plastic hammer, but do it lightly, because remember this is an electronic part.
13. Once that is in and the 5mm allen head mounting bolt that secures the sensor to the hub is tightened, secure the remainder of the cable to the cable ties and plug the sensor into the outlet.
14. reinstall the dust shield, rotor/caliper assembly, and wheel.
15. remove the negative battery cable for 5 minutes to reset any abs codes that may have been set.
16. test drive the vehicle.

I hope this helps you, i now it would have helped me when i started this job.
i have pix, just dont know how to post them in this thread