Power Stearing Issues
 

We have had the typical power steering screech recently, so we decided to drain/flush the existing fluid and put in new fluid. After starting the engine up with the new fluid, it seems to have gotten worse. See the video. Are we looking at more than a fluid issue with the wheel slowing/stopping like that when we turn the steering wheel? Also, if we turn the steering wheel more, we start to hear a whizzing noise kind of like a weed eater. If that happens and we stop the engine, the steering fluid comes out of the dipstick and appears to be "frothy". Air leak somewhere?

Thanks in advance for any help. FWIW, 1970 F100 390 FE 4x4.

Update: We figured the belt wasn't tight enough and pulled the PS pump to tighten the belt and that did the trick for the screeching noise. We will start searching for any air leaks in these very old tubes to see if we can solve the "frothing" problem.

Is this a recent PS swap in the truck? Does the truck leak PS fluid and what type of fluid are you using? If this is a PS swap, what steering gear are you using? Ive never had fluid froth up like you are saying and it did look like the pulley was slowing down in video.

Thanks for the reply. We haven't had the "frothing" problem since tightening up the belt. This wasn't a PS swap, but a removal and reattachment after rebuilding the engine. We just didn't pull the PS pump out far enough on the reattachment. I still think we have a slow leak somewhere due to old, brittle tubes, but need to watch it over the next couple days.

i would think frothing would be air in the system or air being introduced somewhere when the the pump can more easily cause cavitation? i wonder if an improper fluid or mixing 2 fluids that shouldn't be could cause that too?

i recently added power steering to my 67 f100 (saginaw power steering gear from a 73-79 and a gm style saginaw pump from borgeson) this obviously isn't the same situation, but i over filled the reservoir to the top and turned the wheel lock to lock 15 times and after the reservoir was low enough i could see the actual pump mechanism and had to do it again. then when i started it, it pulled even more into the steering gear and if i wasn't paying attention, i bet it could have re-introduced air back into the system. i know i'm making it sound like a lot of fluid... in actuality it was only a little more than a quart.