Hi this can in with alarm ringing brake pedal gone hard and abs light on read codes which said o/s front wheel speed sensor (seemed strange) after a couple of goes cleared and all was fine did a few road test all ok gave bact to customer done bout 30 miles light back on and this time code read 55 hyd brake boots not working which is more like it as pedal is rock hard have checked fuses and relays all ok just wonder if anyone else has had this fault as abs unit is £2500 + vat any help app Wayne