mystery pump - need to fix soon?

[Kneale Brownson]

You talking about the infamous "clacking" vacuum pump for brakes assist
that everyone says in typical Audi overkill (unless you routinely ride the
brakes hard while powering up the quattro system)?  Here's one version of
how to stop the clacking by removing the pump
piston:  http://www.endosquid.com/audi/aud4kfix_vacpum.htm

At 03:45 PM 11/13/2002 -0800, Tessie McMillan wrote:
>There is a pump attached to my engine ('88 5 cyl), on the power steering
>side, just below the cam cover. I've been told it has a piston that runs
>off the camshaft to do its work, but folks I've talked to can't remember
>what it does...  vacuum assist? ABS pump? Anyway, I have a "thwocking"
>sound -- which sounds to me like what a rattly piston would if it were
>whacking away on the cam -- which is supposedly the sound this pump makes
>when it goes bad.
>
>I've also been told I can remove the piston and leave the pump as-is,
>and everything will run fine without repairing the pump.
>
>My two questions are: 1) how critical is it to get this done (am I
>damaging the cam?); and 2) how do I do this? Sorry to be so
>unknowledgeable, but do I try to open the pump, and pull the piston out
>that way, or do I need to take the cam cover off? Third question comes to
>mind: what the heck IS this pump?
>
>Thanks!
>
>Tess
>'88 80 Q, Bellevue WA