Could there be a problem with a sticking piston on the driver's side rear or does the caliper definitely release after you press the brakes? Just wondering if you might have tested with applying the handbrake and thinking it was releasing fine but it could be sticking when you use the brakes?
Could be worth bleeding them, but I'm no expert to be honest. I read in the Haynes manual for the A3 that they should be done in a certain order but not sure how important that is. Are you using a pressure bleeding kit or getting someone to give you a hand?
+1. I have to give a bit of help with the handbrake to clear the surface rust of the back discs if the car has been sitting for the week and that's with recent rear calipers, discs and pads. Don't think the rear brakes do too much under normal braking to be honest.
Might sound ridiculous but I had a similar problem after having the back axle off to do the bushes. The brakes came back into their own after a couple of days driving. Maybe some air was trapped somewhere?
The dealer will try and sell you the whole pipe as the washers are pressed on when new. I didn't have any luck with B&Q so ordered ten size 12x16x1.5 from this seller: eBay - The UK's Online Marketplace
I read somewhere that the "active ingredient" in the Mr Muscle is sodium hydroxide which is the same as what makes the Innotec fluid work. The Innotec kit has a "Turbo Clean 2 is a specially developed rinse agent to neutralise Turbo Clean 1 and to rinse it together with the carbon and dirt...
I'm considering doing this clean up and wonder if it might be better to suck all of the used cleaner out from the turbo using a piece of silicone tube and a large syringe? Could the turbo then be cleaned by refilling with something like diesel, or any other suggestions, and emptied in the...
Are you sure it's £50 from Audi? Last time I bought some it was about £30 from VW. What about a Skoda or Seat dealership, maybe they'd be cheaper if you live close to one.
If not then these guys are really good for mail order VAG parts: Quantum Oil Range - Synta, Longlife, Platinum