'87 TQ Hydraulic Woes

[Michael Spiers <mikes@specnet.com>]

OK, so I'm sitting in traffic in the Turbo Crappo last night on the way home.
 Sat in the same place for about ten minutes, A/C blasting, radio on, foot not
on gas or clutch or brake (level ground.)  After seven or so minutes of NOT
moving, the hydraulic (Brake) light comes on.  Wonderful.  Another three
minutes goes by, traffic starts to move, so I tested the brake pedal to make
sure it still worked.  Lightly pushed my foot on it, and it vibrated lightly
under foot, much like the ABS was kicking in, but I don't think it was the ABS
(no ABS warning lights.)  Another push of the pedal, same response.  Seemed
like the car would stop, so I drove it on home, light never went off, but the
brakes worked perfectly, and the pedal never again vibrated.  Pulled in the
driveway and turned off the car.  Popped the hood, figuring the hydraulic level
was low or something, but the level was so high I couldn't see the top of it,
would probably have squirted all over the place if I took the lid off.  Brake
fluid level was just dandy.  When I first got the car a year ago, I noticed
that the level of the hydraulic fluid was just under the MAX line when the car
was running, but raised to about a quarter or half inch over the line if I
turned the car off.  If memory serves, if the car sat for a while, it went down
to normal, but I can't remember.  It was never this high though.  I drove the
thing 35 miles today to work, no lights came on and the pedal didn't act funny.
 I've noticed lately that if I start the car and just let it sit without
driving, the hydraulic light will come on, but goes away after a mile or two of
driving.  I figured that the A/C (I thing everytime I've seen the hydraulic
light, the A/C is on...) was just robbing juice somehow, so the hydraulic brake
booster (or accumulator or whatever it's called) just wasn't building up enough
pressure.  This lack of pressure is also what I attribute to the hydraulic
light comming on if you turn on the ignition without starting the car and let
it sit with the ignition only on for a few minutes - is this a correct
assumption?  So what's the deal with my car?  What does it mean when the level
is that high after shutdown?  There are no leaks anywhere, and I've never added
any fluid to it.  Do you need to flush the hydraulic system every two years
like the brake/clutch?  Heaven knows when this was done last, car had 124,000
on it when I bought it in October, now has over 145,000, and I've never done
it.  Could this be the problem?  If so, how does one bleed the hydraulic system
in these beasts?  If it needs a new accumulator, anyone wanna buy a TQ?  Thanks
for any help you 'uns can think of!

-Mike
87 5000CS TQ