Re: Bomb replacement problem

["Eric Renneisen" <renneie@hlthsrc.com>]

> Based on these data, I obtained a replacement accumulator 
> (matching Audi p/n as original, newer style with O-rings 
> instead of crush washers) from DADS recycling and attempted 
> the job myself.  

Used bomb? Depending upon age, it's very likely as tired as 
the original.

> I followed the procedure detailed at:  
> http://20v.org/brakprob.htm#bomb and now find that the brake 
> light stays on all the time, braking force is greatly 
> decreased (heavy pedal force required for basic stopping) 
> and steering side-to-side is also difficult (I am avoiding 
> driving it until I know what may be wrong).  

It will take the pump a while to refill the pressure in a 
completely discharged bomb, but you say you idled for 8-9 
minutes, which should be more than enough. I'd first suspect a 
jammed check valve, other clogged orifice in the bomb, or just 
one that has no nitrogen charge at all.
 
> Although approx. 1 liter of pentosin (green 7.1 type) was 
> recovered between emptying the reservoir and disconnecting 
> the hose from the front of the accumulator, only approx. 0.25 
> liter was sucked back in during 8 or 9 minutes instead of the 
> typical 5 minutes of idling during the refill process.  That 
> was the first clue that something was wrong.  

If the fluid level is not going down, then it's not getting put 
into the bomb (see above).

> I performed five cycles of lock-to-lock steering for self-
> bleeding and noticed the pentosin level drop but still used 
> nowhere near the 0.5 to 1.0 liter estimated in the 
> instructions.  I see no evidence of leaks and am trying to 
> figure out where I messed up.

Bad bomb, most likely, especially if it's a used one. If fluid 
can't get into the bomb, then it can't go out to the brake 
circuit, either. That's worse than one that's only lost it's 
charge, because you'll have no assist at all.

Eric Renneisen
'90 CQ 20V  -  my 'racing-iron'  ;^)
Chattanooga, TN