Brake fluid flush procedure (Audi 100, 1989)

Hi everyone,
I've got my Audi 100, 1989 model since ~4 years now and never bothered about the brake fluid. There is a very good chance that the previous
owner never bothered either. I did consider to have the system flushed, but at two independent garages they are hesitant to touch it. One of them recommended to not bother, the other one recommended to go to the Audi agent.
Both of them mentioned that the brake master cylinder could collapse or something like this. IIRC, one of them said this could happen with "all the brake pumping with no resistance". I almost decided to have Audi dealer do it once my finances allow some long-term maintenance expenses. However, I now had a clutch problem and a friend helped me to bleed the clutch with his little pressure bleeder (the one you connect to an inflated tyre and it pushes the fluid through). I am wondering whether the complete brake fluid flushing can be that difficult and risky.
I did a google search but could not find anywhere on this group that anyone mentions a brake fluid flush as a risky procedure (nor on www.audifans.com ). The closest I came was the following statement (I'm not sure whether that's what they are worried about):
"DOT4 or above will do the job personaly i prefer the 2 man job pumping the pedal but on the first few pumps take it real easy as depending on the mileage i have had vehicles flick the master cylinder seals inside out usually on nissans never had it happen on an audi but u never know" (whole thread at: http://groups.google.com/group/alt.autos.audi/browse_thread/thread/dc663c4a4a539bde/292e33214487eb8c?#292e33214487eb8c )
Can I assume that there is no such risk, if I use the pressure bleeder?
Is there any link to someone going through the procedure step by step?
As far as I understand, the propper procedure seems to be: 1) Clutch 2) Brakes one by one starting with the longest line Is there anything else I need to do?
I heard that it might make sense to push out the old fluid with air first before putting in the new one. Would that make sense? Should I get the old fluid out of the clutch and all lines and then do the new one everywhere, or is this stupid?
If the pressure method, do I need to do something to get the old fluid out of the master cylinder (maybe pump once or twice in the process)?
Thanks a lot for your help,
Christoph
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Christoph Bollig wrote:

[snip]
1.) Don't completely blow the system dry! Do take out as much fluid from the resevoir beforehand as possible. You don't want the MC to go dry.
2.) Pressure bleeders are great. And they work. And it only takes one person. Too much pressure can burst the resevoir, so keep it to 10psi or less.
3.) Use the Audi brake fluid. No worries about compatability between parts and fluid that way. You can buy it anywhere on the Internet cheaper than the dealer.
I don't know about clutch first - I always thought it was last.
And finally - search the Audiworld forums for this info - I'm almost certain that's where I read the Audi how-to first.
Good luck.
E.P.
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http://groups.google.com/group/alt.autos.audi/browse_thread/thread/dc663c4a4a539bde/292e33214487eb8c?#292e33214487eb8c
The garage is talking about seal reversal, it does happen but if you pressure bleed, then non of the seals are under pressure.
Don't introduce air into the system, you'll be bleeding it out for hours. Buy the pressure bleeding kit and flush it through, very easy and straight forward.
Nigel
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