1997 Mercury Grand Marquis - ABS sensor removal

I am trying to help my friend remove and possibly replace both front wheel ABS sensors. It has been a while since I did this. We are having trouble removing the caliper (the bolts are rusted on pretty bad) so I just removed the bolt holding the ABS sensor but it won't come out. Any suggestions? I can't remember, but is there a retaining clip?

Thank you in advance!

The only way I've been able to get these off of rusted vehicles is by removing the rotors and hammering them out. Since you can't get the calipers off, I see your frustration. I'd say keep trying with the calipers. Use some PB Blaster.