I have a warning light on my 1996 Peugeot 306 diesel turbo. I know that the warning light indicates a low brake fluid level. When I first found the problem about a month ago, I just filled it up and then a week later I got the warning light again. I did the same, filled it, and a week or two later the light came back on. I haven't actually been able to find a leak around the car, and the brakes feel fine.