Brand new but noisy power steering pump

[Snagglefoot]

I installed an AC Delco new power steering pump. ( not a rebuild). Initially it was dead quiet and I was able to rotate the wheel lock to lock without any noise. I stopped the engine, put my tools away, then started up the engine and low and behold, no power steering. This unit also has a hydro-boost system on it. I left it for the night, then next morning I checked for leaks and there were none. The fluid level was correct. I then suspected air in the system and disconnected the return hose from the steering box ( recirculating ball), plugged the connector to the pump and ran fresh power steering fluid through the pump while rotating the steering wheel lock to lock. Got the steering back. Reconnected the line and topped up. Steering good, full brakes. Drove on a trip of 250 miles, no problems except that the pump is noisy with a high pitched sound. Any ideas on how to quiet it down again? The PS fluid is AC Delco. Wondering if I should pull a vacuum on it. During the 250 mile trip I topped up with about a quarter of a quart. Steering and brakes work fine: just noisey.

 

[Trav]

It definitly sounds like air, try pulling a vacuum on it and leave it under for a couple of hours.

 

[Snagglefoot]

Just a quick update. I used my Mity Vac with the Migty Vac adapter for Chevy’s and so far no luck. I even pulled a 20 inch hg while the engine was running and did the back and forth with the steering wheel and did brake applications. However, I did see some bubbles after repeated brake applications so I have not given up. The truck is sitting with 20 inches of hg on it. I noticed the system bleeds a bit, about 5 inches of hg in a hour. I’m contemplating replacing the return lines.
One from the hydroboost to the pump reservoir, the line from the steering gear the the PS cooler and the line from the PS cooler back to the reservoir. Any other thoughts? Thanks.

 

[Snagglefoot]

Finally solved the noise issue.The powered steering pulley was slightly misaligned causing some belt chatter. I pushed the pulley another 1/8 of an inch further onto the shaft. The snout of the pulley and the end of the shaft are now flush and the nose went away.

 

[andyd]

You beat me to it. That was my guess. Glad you found it first. Treat yourself to a libation for a successful install.