RE: Brake problems.

[rdh@genrad.com (Robert D. Houk)]

   Be careful to determine that your problem is really the pressure accumulator.
   ...
   very common problem.  I'd think that if the accumulator were bad, you'd notice
   increased pedal effort.

Depends on how you use the brakes. In "normal/everyday/gentle" driving
conditions, gently pressing the brakes allows ample time for the engine
to meet brake-assist needs. Only when you "vigorously" apply the brakes
is the lack of accumulator pressure (reserve) noticed. With a dead bomb,
stepping on the brakes is like stepping on a brick - nothing happens at
first. Then (next 1/4 to 1/2 second) the engine/pump has time to pump
enough fluid to meet the "large instantaneous" demand of stomping on the
brakes and the pedal can be felt to move down and the brakes start doing
their job. Very unsettling feeling.

Other than pulling the accumulator and mounting it in a test fixture
(does such a beast even exist?), I'm not sure how one would "test" this
problem. (Short of just "observing" the symptoms and "intuiting" the
obvious fix of replacing the accumulator...)

I guess that after running the engine, then shutting it off, you should
be able to monitor the hydraulic fluid in the resevoir. If it gradually
rises all by its lonesome, you probably have a leaky valve/seal some-
where in the hydraulic system. If it remains constant, even after you
try pumping the brakes 20-40 times, then it sounds like a bad accumulator.
(Hint: to "fill" the hydrauics system, first pump the brakes 20-40 times
until the level stops rising; then AND ONLY THEN fill the resevoir to the
fill line! Otherwise BIG mess!)

					-RDH