There's a line with a banjo type fitting on it that feeds the stand pipe going to the high pressure rails. I think that's a fairly common place to have high pressure leaks. There are a bunch of things it could be, though. How long it will take depends on how competent their techs are and how busy they are. Unless you're lucky enough to be broken down in Winston Salem, that's hard to say.
I wish I could be more help. Maybe Scuffy or Jon will see this and can tell you more.