Steering Noise
I see it can only come from 2 places power steering pump or the kingpins.
I am guessing it is the pump if you said you tried bleeding it.
Did you use ATF or PS fluid?
It also looks like you are running a Ford pump and they have been known to be noisy.
To see if is the pump or not remove the belt and turn the wheels.
If kingpins are frozen they can make noise when turning.
Do they take grease with no load on them?
If you remove the tie rods to each wheel, wheels off the ground how easy is it to turn the wheels by hand?
Dave ----
1966/77 used the Ford/Thompson P/S pump that has a steel reservoir. The P/S pressure hose threads onto the pump..
This pump is known as the "pencil neck" .. because the steel dipstick and the tube it fits into are small in diameter.
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Ford C-II P/S pump introduced in 1978, has a plastic reservoir. The P/S pressure hose has a straight tube with an o-ring on the pump end.
The P/S pressure hose connects to the pump with a qwik connect fitting,
This pump has a large plastic dipstick. From what I see in your pic, this is the pump your truck has.








