When you pull the front hub, does that screw up the bearings? Seals?
The front hub is pressed into the inner and outer bearing cone's (tapered roller bearings). Pressing it out requires that you press *through* the rollers (they will transmit the force) and as such it requires bearing replacement anytime you remove the hub.
From the diagrams, it looks like the tone ring is attached to the hub with allen bolts and doesn't look like it's gotta have the bearings removed to take it off?
It is attached with allen-head cap bolts but unfortunately it only comes off from the inner side of the hub - without removeing the hub from the bearings the hub prevents the tone ring from comming off to the outside, and the knuckle prevents it from comming off to the inside - it is trapped until the hub is pressed free of the bearings.
Where did you pick up your sensor?
The best price I could find was https://www.subaruonlineparts.com for ~$102.
You aren't going to like me after this

...... junk yard. I went and pulled two of them myself. Luckily here on the west coast there is no shortage of cars with ZERO rust. So they come out easily. If there is any amount of rust the sensors are almost always destroyed trying to remove them....... I got lucky on the first try which means I have an extra left rear sensor now which I will sell to you for the $15 I paid for it.... should you need that exact one. I might be convinced to pull one or more of the other's from those same car's for a bit of compensation on the time end of the deal......
Oh - and I just test drove it with the new sensor. Works great. I locked em up in a vacant parking lot and could feel the ABS engage. No light, no codes. So my three codes were really just the code 27. The others were something about a motor/relay and unexpected wheel sensor signals.... probably due to brake dust and gunk build-up which I cleaned away when I inspected each of the sensors.
GD
Edited by GeneralDisorder, 13 April 2010 - 09:20 PM.