About a month ago, my brakes seemed to be losing pressure. The pedal was soft and braking is poor. I took it to a local mechanic and he bled the system and the pressure was better. He said he couldn't figure out how air got into the lines and found no leaks. He also felt that the front brakes were not working as well as they should. He suggested that I take it to a dealer and have the anti-lock system analyzed. Now a couple of weeks later the loss of pressure has returned. I really don't want to take my Discovery to the local dealer. Does anyone have any suggestions?