Replacing front speed sensor

I have to replace the front right ABS / speed sensor as the old one got ripped off with the fender liner. The shop wanted $400 for the job so I went ahead and bought the replacement part myself for $50 (OEM part but used). Is it a simple DIY job? I know there is only one bolt involved (and the fender liner is already out) but i'm wondering if there is any special cleaning or precise placement required to do the job correctly? How much torque should I use on the bolt?