[s-cars] Fix for that annoying UrS "brake" warning light on start-up

[Fred Munro]

	I had a couple of minor annoyances on my '94 S4.

 	One was the red "brake" warning light coming on in the morning for 20
seconds or so after the car sat overnight. This is a common problem with the
UrS cars and indicates the bomb has bled off pressure overnight. The light
stays on until the bomb is back up to pressure. In my case the problem got
worse until the light would come on after the car sat for only a few hours
and stay on for 40 seconds or so. The bomb was losing pressure rapidly
(leaking internal check valve) and was taking longer to recharge. Time for
action!

	The other little problem was a "dead" spot on-centre in the steering feel.
There was no feel and no steering feedback. It felt like a loose tie rod
end, but all suspension components were tight. I adjusted the rack preload
to no avail. This made the car rather unpleasant to drive, as it felt quite
"loose".

I resolved both these problems with one "fix". The brake light never comes
on now, even after the car has been sitting for several days. Steering feel
is back to normal.

What is this miracle fix?

I drained & replaced the Pentosin and cleaned the reservoir strainer. As a
point of interest, I got 48 pumps out of my 9 year old bomb.

The old oil was black as pitch. I suspect the new oil has cleaned out the
bomb check valve, restoring it's functionality, and cleaned out the rack
valving, evening out steering boost.

I'll put together a flush "how-to" with a couple of photos if anyone is
interested.

Fred Munro
'94 S4 (no longer annoyed)