Strange issue with my brakes

[Walker_Bulldog]

Well when I got the truck the brakes didn't feel right at all, the pedal would only move about an inch before getting rock hard. Also it wouldn't return to the top. I jacked it up and one of the tires wouldn't budge so I replaced both front hoses and calipers. That fixed my brake drag but not the pedal return issue. Before the new hoses and calipers the pedal would act the same with the engine running or not, after the new parts the pedal won't return only when the engine is running. Once I shut it off and I pump the pedal twice it returns like it should.

After reading a few threads I decided to check the prop valve reset pin. It was sticking out, I pushed it and after hitting the brakes it pops back out. There was no change in the pedal with the pin in or out. Bad booster maybe?

I have no idea what the problem is, and if anyone could steer me in the right direction I would greatly appreciate it.
Posted via Mobile Device
Posted via Mobile Device