Friction modifiers in P/S pump?

[nonhog]

So I understand Ford gets good results in quieting P/S pumps by adding a friction modifier. I was explaining my intermittent P/S assist loss to a friend who manages a fleet.
He thought I might try the friction modifier before replacing the pump. Already power flushed it as well as new steering gear box.
my issue brakes/steering difficulties has always happened after several miles or hours on bumpy/twisty slow FS roads. Overheating?
Maybe a better cooler too?

Thoughts?

[Astrophysics]

Hi,
I have 2003 AWD Astro with 130,000 miles.
I remove the OEM metal tubing from behind the bumper that was the GM low cost cooler for power steering fluid.
I installed a proper hayden cooler behind the grille and connected to steering hoses to properly cool the steering fluid.
I was having poor power assist at low speed steering effort was high. My 2003 Astro also has hydro boost brake assist which uses power steering pump to pressurize air in an accumulator to act as power brake assist via check valve when you push on brake pedal.

This weekend, I found a loose fitting on the high pressure line going into hydr-o boost, Use flare wrench 16 mm or so to snug fittings.

AP

[Mmusicman]

My 2000's intermittent PS issues turned out to be a sticking valve in the pump.
Changing valves did not fix the problem..
A new pump fixed the problem.

My 92 van had heat and cavitation issues..
A cooler and synthetic fluid fixed the problem.