Ranger trailer proble

[Tholl]

Hey guys .
Having an issue with my brakes I believe. The boat really jerks on stops and starts. It never used to do this . Seems like there is no resistance against it . At the front of the trailer just behind the ball where the sliding bolt looking things are is where the noise is from. It is making loud noises and I know it's going to get worse . Is it possible there is no pressure in the lines ? Any help is appreciated .
Thanks