So today was the day to travel 30 miles to drop off cans and scrap metal. Last night I got a U-Haul trailer, without brakes, and everything was smooth. In the morning I loaded up the trailer, and set off. Total weight was 2,845. The brakes have 53,028 miles on them, but they are in need of replacing. On the way home with the trailer empty, i noticed all of a sudden there was like a popping noie and ABS, VSC\TRAC, and VSC off lights were on. The brakes seemed normal, but I knew something was wrong. I pulled over and check the brake fluid. It was good, and the brakes looked fine from what I could see. I went on, and the lights turned off. Dropped off the trailer, went home. Left about 10 minutes later and came to the end of my street which is about 1000 ft, and i was going 25 MPH, I brake like normal heard a distinct popping sound from the rear, and the lights went on again. I immediately went out and looked all over and could not see anything wrong, I went on and the lights went off yet again. Before I bring it to the stealer what do you think happened?