Bendix brake valve question

[PuroCumminsPower]

The brake valve would leak with parking brakes on or released. So with brakes on I disconnected lines marked delivery or "del" it has supply "sup" as well. I checked each "del" hose going to brake valve until I found the hose that was sending air back into the brake valve. I followed that air line and it connected to the relay valve shown in picture. I’m so glad i found it. Those parts aren’t cheap. Brake valve was like $450 and relay valve like $350.