Hi

I have recently change the front calipers on my A3.
But when I took of the old ones, I didn't use clamp to stop the fluid. It stood like this over night.
Next day, I put on the new ones. Bled the system from, Rear right, rear left, front right and front left. Also I bled the clutch.

But the problem is that, all brakes pads are STUCK on the discs. I went to a local Audi dealer. They said that the master cylinder was the problem.
So I bought a new one. When I took of the old one, I saw dirt in the hole to one of the sensors underneath. Then I installed the new one. Bled the system again, using pressure bleeder.
Now its NO air buubles coming. But the problem is still there...

Pads still stuck on ALL discs. I used VAGCOM, but no fault codes are showing.
Anyone have any idea what the frag is wrong?