Rear brakes have been locking up for years. gradually getting worse. Have replaced rear brakes entirely twice and issues still come back within weeks. Out of ideas. It has rear anti-lock brakes so why would they lock up with minimal foot pressure. Very expensive and annoying. Any ideas?

i have a 2001 dodge Dakota with the 4.7 v8 engine.i bought the truck with 136000 miles an put on about 4-5 thousand miles since i bought it. most of the time when i hit the brake pedal my rear brakes lock up weather its on dry pavement or wet pavement. its getting really annoying an i just don't want to end up rear ending someone because my brakes were not working properly if anyone has any info on how to fix this problem or anything i can do please let me know thanks

toby