73 GMC - power steering issues STILL

[73FrankenTruck]

73 GMC 3/4ton 2wd, 454, TH400, hydroboost brakes.

PROBLEM: When truck sits more than say 12 hours, power steering assist is either non-existant, or about 50% (if that makes sense). Both scenarios have happened. After I make about 3 or 4 turns, problem is gone. It seems to affect right turns more than left, if that makes any sense, either.

HISTORY: This epic battle started with a pinhole in the hose from booster to steering box. I replaced it. Problem persisted. The power steering pump was kind of whiney, so I put in a new power steering pump and belt. After new pump install, no issues for a week. Steering was amazing. Then this morning, it happened again.

I'm out of ideas. The hydroboost unit is new as well. Am I forgetting something? Any insight or advice would be appreciated.

-C

[v30crewcab]

sounds like the seals in the box are worn. I've had a few that wouldn't steer cold. once the fluid flows a minute and warms up it will steer.