hi at my 80s TDI I filled up the brake fluid at the end of october, as the warning light turned on. since a few days, the light starts flashing again at bumpy rides. at the end of october I left approx. 2-3mm air to the max. stand. today I looked again and now it is about 2-3mm above min. stand. but I could not detect any stains on the floor until now (is mostly on bottler, which is usually wet at the time or on grass where you can d as not seen) under the tank in the engine room are also no “wet” spots. do you know perhaps what this can be about? can not be that I can refill dot every 2-3 months again. have also suspected that he consumes oil. have made end october also oil changes and there was the stand on max. now it is about 3 mm under. Thanks mfg