How do you replace the front wheel speed sensor?

I need to replace my front drivers side wheel speed sensor, i crawled under the car today and found the sensor wiring harness and felt the two bolts on each end of it but cant really see anything. How do you replace it and what all needs to be removed to get access to replace it? Any tips would be great too.

Thanks!

Go to autozone.com, repair guides, pretty good info there.

I looked at the autozone repair info but they are saying that the hub/signal ring/wheel speed sensor are one unit and cannot be changed seperately, I know that is wrong because the gm part number for this wheel speed sensor comes up as just a sensor. I also forgot to mention the first time that the car is a 1997 chevy lumina (3.1L).

The front sensors are serviceable. The rear sensors are integral to the hub. From the 1997 W-Body service manual:

http://mysite.verizon.net/strey/files/W-BodyLFWheelSpeedSensor.jpg

I thought the other info was wrong and that the sensor was serviceable. What needs to be removed to get the best access to this sensor? Or do you just have to blindly try to make the ratchet and extension fit in there?

There are two M6 or M8 bolts on the back side of the hub. You should be able to turn the wheel inward (to the right) and access the bolts with a box end wrench.

There are two M6 or M8 bolts on the back side of the hub. You should be able to turn the wheel inward (to the right) and access the bolts with a box end wrench.Are those two bolts the ones that hold the sensor? I was having trouble finding the right socket for them any idea what the bolt head size is?

Does anyone have any more info on changing these sensors? What size is the bolt, and do the wheel or hub need to be removed to change the sensor? im asking because it looks like it would be hard to get to them being they are in a tight area.