[urq] bomb test variation with S4 brakes?

[brady zq]

Ok, just went and checked bomb drinking capacity.

When empty, the ATF is at the top of the line that is stamped into the 
reservoir. And that is about 0.7cm below the top.

When the bomb is full, the level drops to about the bottom of the white 
plastic filter, which is at about 4.5cm ish from the top. I can't see below 
this, but it sure looks like that is the level.

So, the total drop is approx. 3.8ish cm, or about 1.25".

I didn't measure the ID of the reservoir, but just as an estimate, I'd say 
from recent memory it's about 4" or 10cm, give or take the volume the filter 
displaces.

So, pi x (5cm)^2 x 3.7cm = approx. 290ml. This is about what my bomb drank. 
And this time I got 14 pumps. So, figure on about 20ml per pump if that's 
useful.

What is the capacity of an oem urq bomb? And at what pressure? The bomb's 
capacity for ATF should be the difference in the volume of the nitrogen 
bladder at max pressure (bomb full of ATF) vs at min pressure (bomb emptied 
of ATF) . Right?

Ouch, my brain hurts.

The one mentioned in the  archives that x-ref's with the BMW 733i is 480ml 
and 100bar. This is what I have, though without those marking stamped on it.

There is no moisture on the floor under the pedals. I felt the rod to the MC 
and it is dry. And there is no brake fluid consumption.

So, maybe if the pressure is higher in this bomb, as it wears out, I will 
actually get MORE pumps before I get  fewer. Nice!

Or, maybe my hydraulic pump is wearing out....

Cheers,
Brady

>From: "Martin Pajak" <martin at quattro.ca>
>
>Brady,
>
>Have you checked for moisture on the inside of the car?
>My old '83 had a leak in the booster on the inside of the car.
>Nice puddle of fluid under the carped beneath the pedals.
>
>With as you describe "pedal travel is now and has always been pretty short
>and firm"
>There should not be a decrease from 30 to 10 pumps from your bomb.
>I can see decrease from 30 to say 25.
>Did you check how much fluid actually goes into the bomb?
>If the charge press in the bomb is high it will not allow it to fill up to
>capacity.
>
>Hope this helps.
>--
>Martin Pajak
>
>http://www.quattro.ca
>
>1982 Audi Ur-quattro (50,000 mi) new project
>1983 Audi Ur-quattro (85,000 mi) Concourse d'Elegance
>1985 Audi Ur-quattro (212,000 km) Euro spec. import mit 3B :)
>1987 Audi 4000s quattro (205,000 km) wintervagen mit 7A :)