I have a 1997 f150 xl v6 4.6 only rear abs. My problem is that my rear wheels (specifically passenger side locks up before the rest and my brake shimmy on the wheel is ridiculous even with all new rotors/drums last summer. They feel like they should when u push the pedal but the back is grabbing before the front. Heres some details

ABS is ON and 9 flashes for the code
ive replaced Masyer cylinder, all lines in back and rubber hose, rear wheel cylinders, rear abs sensor (3 times) and swapped out my proportioning valve from a truck same year and model that was in a junkyard.

 

we are debating selling the truck over this :/

 

Maybe the drum hardware? That's all I've got, don't think it could have anything to do with the e-brake...

 

If they grab in the rear before the front then make sure they are adjusted properly. And if you have cheap-o shoes in the rear, when they get moisture on them then that can cause them to grab. As for the code nine, im not sure.