disconnected wires

[Mike Arman]

>From: <audifan at spymac.com>
>To: quattro at audifans.com,
>Subject: 1990 200 Quattro brakes?
>Reply-To: audifan at spymac.com
>Date: Wed, 02 Oct 2002 10:53:03 -0600
>
>Thanks for all the previous help!
>There is an electrical connection on the back of the master cylinder,close
to firewall.
>When I purchased the car it was unplugged. Two blade type connections.
>When I plug back in the brake idiot light comes on. when I disconnect no
light.
>Does this have any thing to do with the "bomb".


Sure does.

The "bomb" is a pressure accumulator for the brakes. It looks like a Boris
and Natasha cartoon hand grenade (black sphere with handle sticking out),
hence the name. It lives just behind the left front wheel, inboard of the
frame rail.

When the bomb looses pressure (the nitrogen bleeds out slowly - bombs
typically last 5-7 years), the brake idiot light comes on. Since a new bomb
costs $200 to $250 (YMMV), when someone sells an Audi with a dead bomb,
they disconnect these wires and that keeps the light off.

Russ Southerlin (e-mail address, anyone?) recharges them for a LOT less
than a new one costs.

While you can drive the car without a working bomb, you shouldn't. The
brakes might *feel* OK, but if you really, really need them (like some
child on a bicycle cuts in front of you), there's nobody home. When you
replace/recharge the bomb, the first thing you will say is "WOW" or "Oh
sh*t!!" (50/50 chances) because the brakes will work SO much better.

The test for dead bomb is as follows - park car, pump brakes with engine
off. The brake pedal will feel very hard in three or fewer pumps, like
stepping on a board. If you can, try the brakes in an Audi with a working
bomb, and you'll immediately feel the difference. (has to be a
5000/100/200, no bombs in 4000/80/90s) A good bomb will deliver 15 to 25
strokes before the pedal gets hard.

Takes an hour or so to change one the first time, much less subsequent times.

Best Regards,

Mike Arman