My son's 2000 Ranger, 2.5l, 2wd tore the timing belt a couple weeks ago. We towed it home and pushed it up into the driveway. After getting it up there we noticed power steering fluid on the underside of the hood.
We, did a timing belt/water pump this last week, finally getting it back together this weekend.
When we were burping the coolant system, we drove it around a bit. It seem to shudder when turning the wheel.
Thinking there was air in the PS system, tonight I lifted the front wheels up, and turned the wheels slowly from lock to lock. It seemed to do fine until I turned them faster, then would start shaking...and frothing in the power steering tank until I shut of the engine.
So... is that pump going bad symptom, or do I just need to take it slower, or do it by leaving the weight on the wheels and driving in slow circles?

 

Update on this.
I sucked out the old PS fluid from the reservoir, added fresh in.
Then took it real slow at first turning from wheel lock to wheel lock. ...for the most part, it's the same I did before, but didn't let it start frothing and bucking, which probably added more air into the system.

 

it needs to be bled of air, once this is done it will not shudder like you describe.

 

My understanding of how to bleed/burp the air out, is to (while running) jack it up to get most of the pressure off the wheels. Then with the reservoir cap off, tune it from wheel lock to wheel lock, which will force the air out. Then drive it in slow circles and do the same.