I think the rear disc gives you the capability of "ABS on the rear" that is standard now. That capability involves Master Cylinder changes under the hood.
Good luck...

 

Mine is a Lariat, so I already have 4 wheel ABS, does anyone know if the ABS controls and master cylinder are the same for disk and drum? Also, I plan on taking the limited slip diff. from the same axle to replace my open one, they are both 8.8s so I assume this is no problem. Thanks for any replies.

 

I have a 97 F150 4x4 with 4wabs. I want to add rear disc brakes from a 99. Is this a straight forward bolt-on?