Hello


I have a 2016 A6 3.0T, 65k miles. Only previous issue was at about 30k miles I had the supercharger clutch replaced under warranty. Front rotors were warped when I bought the car but the pads were fine... I kept driving.


Brake pad indicator came on recently so I decided to replace pads and rotors on all four. Pad/rotor replacement went smoothly except for having to beat the crap out of the wheels to free them from the rotor. I replaced the front driver's, then the front passenger's side. Pistons pushed in smoothly. No leaks anywhere. I've changed brakes on several cars over the years and never had any issues.


When I went to break in the new pads (I hadn't replaced the rear yet), the pedal feel was off. It was very spongy and way too much travel--nearly to the floor before I got any bite. Pumping would firm up the pedal but it would slowly sink if I held it at a stop. Local shop suggested bleeding, which didn't make sense to me at first because I didn't do anything (I think) that would have introduced air.... so I bled both front calipers. It felt better, pedal was more firm and didn't sink as far as it did before I bled them, but it still took a lot of pedal travel to get it to bite. Sooo I dropped it off at the shop to have them take a look. They bled the brakes again (they said "not a lick of air in there"), but it didn't solve the problem.


Now I have new pads and rotors in the front and old, VERY worn pads in the rear. The shop thought it might be the difference in front vs. rear pad height that's causing the problem. Is that possible? Anything else I should check or consider?


Thanks in advance for any help you can provide!