Problems with brakes on both axles is more prominent on a flat bad car hauler or a utility trailer. When the trailer is unloaded and you use the brakes, when the front axle stops this causes the axle to be pushed toward the rear of the trailer. This in return causes the equalizer mounts(the parts that connects the front leak to the back leaf) also to be pushed backwards. When this happens the rear axle it lifted in an upward movement. It continues this and has a tendency to try to climb over the front axle. My trailer when empty, has a bad tendency to hop and skip to a stop. If I disconnect the front brakes, it stops normal.