Re: pressure accumulator improvements?

[Bob Kunz <bkunz@hpbs114.boi.hp.com>]

> 
> 
> thanks to the discussions here, i had the pressure accumulator replaced on
> the v8 last week and all symtoms (i.e. brake light staying on for 30 secs
> after cold start) disappeared. 
> 
> anyway, the side effect of this change is that there is slightly
> more power assistance to the brakes.. a great improvement actually.
> i don't have to press as hard now if i want strong retardation and
> holding the car stationary in "D" is now real easy.
> 
> i was wondering if this was due to the bad accumulator losing
> "boost" or if this was a subtle change that they made...
> 
> anyone?

The pressure acummulator "king" speaks:  :-)

The effect you notice means that your hydraulic pump didn't have the
output capacity needed for normal driving without a reservior to meet
the peak demand. But that's OK. It's supposed to work that way. 

The system works just like a private well and tank combination. No one
would expect the well pump to meet instantaneous demand for water so it
meets average demand and uses a tank (capacitor for you EE types) for
the peak demand. Same thing with the Audi hydraulic assist system. The
accumulator is there to meet peak demand as you have found out.

Just a reminder for the rest... DO NOT USE "JACK OIL" IN THE HYDRAULIC
CIRCUIT. USE PENTOSIN OR EQUIVALENT. This is most important.

Happy motoring!

--Bob Kunz