John, not sure on this one.  At first I thought the idea behind was to keep
the power steering pump with a steady supply of oil.  It keeps the pump
from cavitating due to lack of fluid.  That is why, if you make a new hose
without it, you hear a groaning sound coming from the pump at all times
(not just when you turn the pump full chock which can be normal).

However that theory seems to be disproven by folks who have replaced their
metal power steering lines (long ones from front to back) with rubber
lines.  I sell these all the time, and if you replace the metal lines and
install a high pressure short line to the pump without the restriction
piece there is no growl.  So it almost seems like the restriction piece is
there to prevent some type of harmonic resonance that develops from the
long run of metal pipes with high pressure power steering fluid inside.

That's all I know on this one.  Hope it helps you out.

Ken

On Fri, Jan 15, 2016 at 9:42 AM, John Rodgers <jrodgers113@gmail.com> wrote:

> Can anyone explain to me what the restrictor in the high pressure hose from
> hydraulic pump to metal line does, and how it works to do its job?
>
> Looking for enlightenment!
>
> John
>

--
Thanks,
Ken Wilford
John 3:16
www.vanagain.com