Just wanted add to the list of those saying a massive thank you to VagPro
Had the same problem occur all of a sudden yesterday, with no prior warning. Dropped the roof in the sunshine earlier in the day but when I got home nothing - it wouldn't go back.
Struggled to get it back manually. Even though the roof lid popped up a few inches, so I was then able to lift it completely, I could not lift the roof itself, even with 2 people. After quite a while, I tried using the manual key and bingo - so it must somehow also release the hydraulic pressure in the system too. And I just thought it released the lid.
So having finally got the roof closed, it gave the classic symptoms of opening an inch or two then nothing.
Now for a bit of a back-story ...
I bought the car from an Audi main dealer 3 years ago, when it was 4 years old. The day before I was meant to pick it up, they called to say the roof had stuck in the down postition, and they were having to replace the hydraulic pump and other bits at a cost of nearly £2000 - I saw the 'internal' bill so I know how much it was (pump £1000, storage box £300, + bits and labour).
Then, within the year (and so still under warranty), I noticed that the rear demister only had about 3 bars working, so I took it back - to which they said the only solution was to replace the whole roof hood, as the glass was bonded into it. They refused to do it as it was 'too expensive'. I kicked up a big stink, and eventually they relented and changed the hood. A few months later I noticed the bars were not working AGAIN, and to cut a long story short, they changed the hood AGAIN, under warranty.
So fast forwarding to now, as you can imagine, I was really p...ed of last night, worried it would be a £2000 bill to me this time, for a new pump and labour - but then came across this thread on Google.
With a bit of trepidation, I followed the instruction in the first post to a 'T'.
OK - it was a bit fiddly getting the trim out etc, but once that was done the motor came out easily, and after cleaning the commutator and freeing the brushes it all worked again a treat.
Start to finish was under 2 hours, but I took it slowly and tested a few times before bolting everything back an refitting the trim. If / when I have to do it again, I reckon it will easily be under an hour now I know what to do.
Out of interest, I notice a puddle of what I imagine to be hydraulic oil under the pump, almost certainly from when the dealer replaced it (the level in the pump now is fine). Also, the trim by the roof box was catching every time the box was lowered, as it clearly had not been refitted by the dealer properly - but is now sorted !
What is really worrying is reading all the stories on here of the same problem, down to the same motor / brush / commutator issue. And, it is highly likely that the problem the dealer had just before I got the car was the same issue. It seems that the motor only has a life of around 3 or 4 years
And I thought Audi's were well engineered !!!
But anyway, thanks again to VagPro, and I will drop a crate of beer into to you if ever I am in the Leicester area
