JC,
I’m assuming also that the ENTIRE retract system is hooked up (plugged in). I found out that testing the valve without the air cylinders connected to valve, it will leak down. Even if both the retract air line and the extend lines are connected together. At first I thought I had a bad valve, before hooking up all air cylinders. I’m using the Red Robart valve and have had no problems. Hope this helps.