A6 Brake Problem. Any Audi mechanics out there?
 

I have a 2000 A6 2.7T and needed new brakes on the rear. The calipers were frozen so I got Lucas factory replacements and had my mechanic replace them. His shop has been taking care of all my cars for over 30 years and he has done a lot of work on my Audi. When I picked up my car there was a slight problem with one of the springs on the brake pad on the left being pinched do he took a look at it, diagnosed the pinched spring and fixed it. I drove the car and thought the brake pedal was spongy and too close to the floor. They bled the brakes (all 4) until they couldn't get any more air out of them. The car stops well but the brake pedal is still spongy and too close to the floor. Wife noticed it too and felt the car wasn't going to stop when she drove it the first time.

Question is: Does anybody have advice on what might be happening? No fluid leaks anywhere. Good pads in the front and rear with new Akebono pads and Brembo rotors all the way around. Only the rears were changed - the rotors, calipers, and pads. Topped off with DOT 4 brake fluid. No brake warning lights. Emergency brake tight - 3 or 4 clicks.

Help?

Thanks.