Driving a car with a brake oil problem can be very dangerous as it can lead to a decrease in the overall braking performance of your vehicle. This can make it difficult to stop your vehicle suddenly in an emergency situation and can lead to longer stopping distances. It can also increase the wear and tear on other braking components like the brake pads, rotors and calipers, which can increase repair costs. In worse cases, it could also put your life in danger. Therefore, if you suspect any problems with your brake oil, it is important to get it checked out by a qualified technician as soon as possible.