Nothing brings us all more joy than squealing brakes.
Its just one of those things that drives you up the wall! The A8 QS has the Girling setup and when I purchased the car the brakes had seen better days. So recently I went to ECP and bought all new Pagid Discs and pads all round and fitted them to the car.
They were Ok for a while but then the fronts started to squeal at all sorts of brake pressure levels.
So:
1) Cleaned everything and put it back together, still squealed.
2) Put copper grease on the pads, still squealed.
3) Put red grease on the pads, still squealed.
4) Put white grease on the pads, still squealed.
5) Used anti squeal rubber pads and that actually helped a little but it still squealed.
Hence at this point it was getting rather frustrating, everything was clean and I had also tried copper slip on the hubs to see if it was the mating of the disc to the hub that was the problem but that did not help either.
Solution?
I put some Mintex pads in, dry, straight out the box and no more squeal
Seem to bite and brake a little better also which is good news, no idea if its the design or the compound that has resolved matters but its quieter now!