Hydraulic system problems ('85 5000 turbo)

[Kneale Brownson]

At 11:16 AM 8/18/2006 -0400, Ameer Antar wrote: 

>
> The only other weak point I can think of is the brake accumulator; this was a
> rebuilt one. Could this be causing these symptoms? Any more advice or
> diagnosis procedures is much appreciated.


The test for the accumulator is to run the engine above an idle (like after
you've driven far enough to warm up the hydraulic oil well), shut off the
engine and pump the brake pedal repeatedly until you go from a normal feel to a
stiffer feel.  Anything under about 20 pumps indicates a failing accumulator. 
Anything under five pumps indicates a dead accumulator.  

There really is no "rebuilding" in the sense of taking the sphere apart and
replacing the bladder that flexes to compress the nitrogen gas on one side of
it while the oil is under pressure and then holding that pressure for use as
the brakes are applied without the engine running.  A bad valve that releases
pressure prematurely can be tested for and replaced and the bladder can be
tested to be certain it holds a charge for a while, but it's impossible to tell
that the bladder might let the gas escape over a month or so, I'd think.  Or
might just fail shortly after being put back into service.