Bomb....Bad Bomb

["Al Powell" <APOWELL@agcom.tamu.edu>]

"Paul C. Waterloo" <74543.407@compuserve.com> asxked:
> On my '87 5KSQ, the brake warning light comes on every now and then.  It started
> late last summer, especially when it was hot outside.  It would normally come on
> after a hard brake, and then not reset until the car had been sitting idle 
> overnight.

> It still comes on, I've been testing it lately.  If I brake real hard, it 
> doesn't come on, but after I brake hard the second time within a short period of
> time, it comes on.
>      
> Also, I have noticed that it has come on when turning the wheel at low speeds (a
> lot of wheel turn), and not during braking.

Paul - as others have commented, your description indicates the 
pressure accumulator, aka  "da bomb" (looks like WWII potato masher 
grenade...) is failing.  This is a metal bottle filled with nitrogen, 
into which  the power steering/brake hydraulic system pumps pressure. 
The nitrogen provides a pressure buffer to keep you from feeling the 
pulsations of the piston-type hydraulic pump, and also to provide 
pressure assist for the power brakes.  This is a common failure in 
Audis, and tho expensive at a dealer, is VERY easy to do yourself and 
VERY much less expensive when you buy your own parts.

And the Hon. Robert Myers <rmyers@wvit.wvnet.edu> replied:
 
> The pressure accumulator, if that is the problem can be obtained from 
> Linda for consideraly less than the $400 mentioned below.  A bit ofer 
> $200 as I recal (if you call 50-60 a bit).  A hour of labor is about right.

I'm confident you can find this part for $200 or UNDER.  Check 
Carlsen, but also check Blaufergnugen and AudiOnly.  I'd bet at least 
one of them will be under $200.  These guys should be in the Web page 
vendor list.

One hour is PLENTY to replace this part.  You will need a pan to 
catch dripping fluid and about 1/2 liter of Pentosin to replace the 
fluid which is lost in the operation.  Make SURE you get the correct 
kind Pentosin for your hydraulic system, as there is a type 7.1 and a 
type 11.  The year of the vehicle determines which is correct - the 
newer ones use type 11.  Plan on getting your left arm and both hands 
real slippery with Pentosin.

Even the first time I tried this, it took only 45 minutes.  Email me 
for a complete itemized procedure to do this replacement.  If you 
want to see it, look just inside the driver's side tire well for a 
horiizontally mounted black metal part about 12 to 16" long with 
two hoses bolted to it and one small one one its rear tip, connected 
with a hose clamp.
 
> With a totally shot PA neither brakes nor steering work right.
> 
> The definitive test for a bad PA:  Run the engine for a couple of minutes 
> to allow the PA to charge its best.  Turn off engine and repeatedly press 
> the brake pedal, counting presses, until the pedal starts to feel hard.  
> 30 or more presses and the PA is OK.  10 or fewer = replace it ASAP.   
> 15-20 = keep a watch on it and be prepared to replace it before long.  
> When it gets down to 1 or 2 = you ain't got no power assist on brakes or 
> steering.

Agreed mit Senor Roberto.  I replaced mine and I still get a warning 
light for a while during the first few seconds after start-up, but 
I've learned to live with it.


Al Powell                           Voice:  409/845-2807
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