I have reactivated a Knudsen Taunus, who stood in a garage for 20 years. The Taunus is in itself well there, also has a fresh H approval. Unfortunately, I have the problem that after a few kilometers drive, the front wheel brake no longer opens. As part of the reconstruction I have revised 1. the old brake calipers with reperture sets 2. all rubber lines replaced 3. Brake power amplifier and main brake cylinder as well as discs and brake pads. But that doesn’t seem to be the case. Since everything is new now, I honestly lack an idea where the problem might lie? If you start with a cold engine, the Taunus will brake wonderfully. Just as it should. After a 10 km drive, the brake won’t open properly. Does anyone have an idea what this might be about?