I had the master cylinder replaced back in the fall . At that time they said also that the booster needed replacing now or at some point in the near future. Being on a budget I opted for the latter.Well , the other day the Brake (red light, like when the Parking Brake is engaged) light came on and has stayed on . I checked the fluid and all looks good , but there appears to be two chambers to the fluid reservoir . And one is low and I don't seem to have access to that chamber . I'm not sure where to start with all of this .