I recently had a problem with the roof slowing down and eventually stopping on my A4 Convertible. I consulted the forum and came across an excellent article from Krumz in relation to cleaning the hood motor. Link to the article as below:
Audi A4 Cabriolet Soft Top/ Roof / Hood Motor Repair Guide
I followed this article and did exactly as described but unfortunately this did not cure the problem. In the article was a link to a chap on Ebay who rebuilds motors so I got in touch with him as he was fairly local to me. Link below:
Audi A4 Cabriolet Roof Motor Repair (Power-Packer) | eBay
In short while the A4 was in to the local main Audi dealer (York) for a cambelt change I asked them to diagnose the hood fault and was told I needed a new pump which would be £1200 plus!
When speaking to Mervyn (Ebay chap) I described the symptoms of the hood not working and he immediately confirmed it was a motor fault as the original brushes fitted to the motor are of poor quality. He also advised that rarely do the pumps fail and that he had reconditioned hundreds of motors.
I visited Mervyn and within half an hour he had cleaned the bushes up and confirmed the motor was working fine. This did the trick but the hood still struggled which was down to the pump not having enough hydraulic oil in the reservoir. Topped up the oil and the hood now works perfectly.
The article from Krumz was spot on and very comprehensive. Mervyn is very helpful and his contact number is in the link. He does a very quick mail order service for your motor as described in the link.
Overall this solution cost me £30 for Mervyn to clean the motor (I had already removed the trim to gain access) and £8 for a bottle of hydraulic fluid from Audi. Total £38 as opposed to £1200 plus from Audi!!!
Do not have faith in main dealers, they mis-timed the new cam belt when fitted and the car had to go back to be set up properly and on a health check they completely misssed a tyre that was illegal on the inside despite them stating it had 5mm!
Hope this post helps as the links saved me a fortune.
Thanks again to the forum, Krumz and Mervyn