hi can anybody help, have got problems with brakes on sirion el, the pedal goes to the floor have bled the brakes with new fluid and all was fine until i started the car then the pedal went to the floor again again, replaced the master brake cylinder with another one but this made no difference pedal was firm but as soon as car was started brake pedal went to floor again, was told this could be the brake compensator, have tried to locate but unable to find this. think the problem is the master brake cylinder but was told the used part was ok,has the ignition switch got to be turned to the || position when brakes are bled