Good day, I’ve been having an 88 Audi 100 c3 quattro with NF engine for 3 months. Rebuild it since then. As far as good as the brake. The rear left brake is stuck. I have previously renewed the piston seals and cuffs on all saddles and naturally new guide sleeves and pads. Brake cracks at the rear and hoses are also new. There were no problems when assembled. I have ventilated by hand and with underpressure machine. Is everything tight. Can it be that of the brake force regulator what has to do with it? I have made the wippe walkable and the spring is also new. Or is it on the saddle itself? Mfg M