Hydroboost Brake pedal not retracting fully

[KRS1]

Hi Guys, I have a '88 1 ton with hydroboost assisted brake pedal. I finally got the truck on the road and was doing some "shake down" laps in my neighborhood. I have replaced the steering box,all the lines and the pump. Initially, I had problems getting the air out of the hydroboost system and I tried to bleed the hyrdroboost system a lot! It seems like I finally got the the power steering pump to stop "moaning" but then the brake pedal started to act up. It wouldn't return the fully retracted position and would "drag"...
The brakes were working fine before, can I assume that the air in the system has made it's way from the pump to something affecting the braking system? Now, I sometimes hear a "hiss" when I push the brake pedal as well. I did fully bleed the brake system awhile ago and it seemed to be the proper firmness..

 

[454cid]

I don't know, but my hydroboost hisses, too.

 

[KRS1]

I took out the truck for "break in laps" around the neighborhood (for like 1 hour) and the brake pedal situation didn't occur. I guess the thing is; perhaps now the hydraulic assisted system is bled? What do you guys think of the moaning sound from the pump? Is this normal now?

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[Astro]

Man I'm having a similar issue. Not really the noise, but the pedal likes to take its time disengaging. I can't think of what may be causing it. There doesn't seem to be any air in the power steering.