How do I fix the brake system in my Audi 80?

I have noticed that my Audi 80's braking system is not functioning properly. The brake pedal feels spongy and there is a noticeable decrease in braking power. What could be causing this issue and how can I fix it?

Based on the symptoms you described, it seems like there could be air in your brake lines which is affecting the braking pressure. I recommend bleeding the brake system to remove any trapped air. This can be done by following the proper steps outlined in your Audi 80's manual.

Another possibility could be that your brake pads have worn out and need to be replaced. Check the thickness of the pads and if they are too thin, it's time to get new ones.