RE: How can you tell if "the bomb" is bad?

[Aleksander Mierzwa <alex@matrix.com.pl>]

Indeed, if the pedal vibrates, it is a good indication of a dead bomb. I
would suggest one more test, though: run the engine for a minute, switch
it off and count how many times you can apply brakes until you loose the
assist. Less than 10 times = bomb is marginal, less than 3 times = bomb
is dead. Both test are only valid if the pump supplies enough pressure
and the servo isn't leaking at mega rate. As to safety issues, well, I
have driven my 5K with a dead bomb for 3 years. I have also driven
couple of miles without the power assist at all and now I have finally
installed the new bomb. I can tell you that you really can't feel any
difference it brakes feel until you have to make a panic stop. If you
have to stop really hard and you have a dead bomb, the pedal gets hard
and starts to vibrate, but even me, a computer geek who hasn't worked
out for ages ;-), can bring the vehicle to a stop quite efficiently. 
The price seems about right. You can get the 5K bomb for about $240, but
I believe '91 200 uses newer bomb, wich is likely to be more expensive.
The job takes a skilled mechanic about 0.5-1 hour, so Bob's labour costs
are a little bit high, though.

Aleksander Mierzwa
Warsaw, Poland
mailto:alex@matrix.com.pl
87 Audi 5000CS turbo (mine)
88 Renault Medallion wagon (mom's)
91 mountain bike (just in case both cars broke at the same time :-)

> -----Original Message-----
> From:	Gary Bracken [SMTP:gbracken@dimensional.com]
> Sent:	Wednesday, March 18, 1998 11:35 PM
> To:	Quattro List
> Subject:	How can you tell if "the bomb" is bad?
> 
	[...]
> Bob there tells me the brake accumulator is bad and poses a
> safety hazard if not replaced.  Says he tests by hitting the brakes
> hard
> 3 times in a row (sitting still with motor running).  Says on this
> car,
> the third time he hit the brakes the pedal went down about 1.5 inches
> and then the pedal began to throb.  He said that's a dead giveaway
> that
> the bomb is bad, and that the brakes might not be safe in an emergency
> situation.  Does that sound right?
> 
> The owner of the 200q says the brakes work just fine, so he doesn't
> want
> to pay for having the bomb replaced.  I'm going to drive the car back
> to
> Denver (if the deal is consumated), so I'm a little concerned about
> safety issues.
> 
> By the way, the mechanic says $300 for parts and $75 for labor.  Does
> that sound reasonable?
> 
> Your quick reply would be most, most, most appreciated!  Call me
> collect
> if you like.
> 
> Gary Bracken
> Denver, CO
> (303) 969-9964
> '87 4kcsq