I have a 2004 coupe and haven't been able to drive it for a while. Over the winter the battery died and despite trying to charge it, it wouldn't take the charge.

The battery was old, so I decided it was time for a new one. Replaced the battery and everything seemed happy until I stepped on the brakes. I have always had good firm brakes. Now they are spongy and need to be pumped to stop the car. If I don't pump the brakes, the BAS/ESP light comes on.

When the battery was going low, the spoiler would come up when I started the car. It seems OK now with the new battery.

The brake fluid is at the right level. If I didn't know better, I'd say that the system needs to be bled, but no one has touched the system and there's no reason that air would have gotten into it.

Any ideas??