Hello I hope someone here can give me advice I loaned my Hyundai to my son and he suddenly had no brake pressure anymore he kicked the brake a few times but nothing when he came to the stand he called me I asked him again to kick the brake but also nothing I have tried when I was with him and not to a free workshop that my brake force stanchion or main brake cylinder is leaking out because nirgens brake fluid, I have exchanged both ha parts used buy from the dealer and still he does not build any brake pressure on the brake circuit was also ventilated and it came everywhere when venting brake fluid no but no pressure I hope someone can help me further have read that with different cars when air comes into the ABS you need a special venting device. can this be the case ?????