98 Ram 1500 Brakes?

I have replace the brakes on my truck once already including calipers because my truck was jerking when braking. That was 7000 miles ago. Now its back. I can feel the jerking in the brake pedal. Seems to get worse when the brakes are warm. Also I don't think my ABS is working. Are the problems related and is there a fix?

could possibly be a warped brake rotor...or a drum on the rear if there is drum brakes on it.