1999 Silverado K1500. No Power Steering

google power steering pump whining

There may be air trapped in system, or pump could be bad.
Vehicle this old inspect hose and replace if they are leaking.
Good Luck

https://gobdp.com/blog/how-to-fix-power-steering-pump-noise/
https://www.fixautousa.com/blog/signs-of-bad-steering-pump/

better to replace if kinked just disconect form both ends wherever its conected put new pipe on refill power assist resivwar and turn steering lock to lock when started

I had the same thing happen. In the end it was the mechanism that attached from the pump to the lines there was a little metal piece with a spring that im guessing kept getting stuck

YOU HAVE A RUPTURE PRESSURE LINE IF YOU HAVE NO POWER STEERING FLUID IN THE POWER STEERING RESERVOIR.LOCATE LEAK THEN BLEED POWER STEERING SYSTEM BY ADDING POWER STEERING TO RESERVOIR.DONT OVER FILL BY FULL COLD MARK ON POWER STEERING DIP STICK.ADD FLUID TO RESERVOIR WAIT A 2 MINUTES.CHECK FLUID LEVEL AGAIN.WHEN POWER STEERING FLUID LEVEL STOP DROPPING.START ENGINE LET IT RUN FOR 10 SECONDS.THEN TURN OFF ENGINE CHECK POWER STEERING FLUID ADD FLUID IF FLUID LEVEL DROPS. WHEN FLUID LEVEL STOP DROPPING.SAFELY RAISE SUPPORT VECHICLE FRONT WHEELS.START ENGINE.NOW TURN STEERING WHEEL GENTLY FROM STOP TO STOP MEANING LEFT TO RIGHT DONT HOLD IN POSITION.LET THE STOP TO STOP BE QUICK.CHECK POWER STEERING FLUID AFTER YOU HAVE TURN STEERING WHEEL ABOUT 7 STOP TO STOP.WHEN FLUID LEVEL STOP DROPPING YOU AT HOT MARK ON DIP STICK BLEEDING PROCESS COMPLETE.TURN OFF ENGINE LOWER VECHICLE BACK TO GROUND WAIT ABOUT 5 MINUTES CHECK YOUR FLUID LEVEL.IF FLUID LOOKS LIKE A TAN COLOR.YOUR POWER STEERING SYSTEM FULL OF AIR.TURN OFF VECHICLE LET VECHICLE SET A LONG WHILE TO AIR BUBBLES SETTLE DOWN LOOK FOR LEAKS AROUND POWER STEERING PUMP FRONT SEAL AND CHECK FOR LEAKS AROUND POWER STEERING LINES.

power steering is at the front of the engine and runs on the belt. The reservoir cap looks like this:
To top off steering fluid, use standard steering fluid.

The reservoir in front of the brake booster is the brake master cylinder reservoir. To refill, use standard brake fluid. If it the truck is using brake fluid, check for leaks at the back of the master cylinder and at all wheels.

Please let us know if you have more questions.

it could be a spun baring inside the power steering pump. if the pressure on the pump is to great for to long of a time it will spin a baring or pop seals.

If your steering is easier above idle the problem is the pump.

Get yourself some Lucas Oil.
Remove about a cup of oil from your power steering reservoir.
Replace with a cup of Lucas Oil
I used it on my truck steering and within two days of running no more steering problems

Because the oil is too think. Check with GM about a low temp substitute.

You're going to have to bleed the system alot on those trucks. Just remove the return line and have an assistant turn the steering wheel back and forth just enough to engage the pump and filling the resevour while doing this. Keep bleeding until you have a good flow of P/S fluid out with no air bubbles. This can take a while.