I have 2002 lexus gs300 with 70k. I did a brake caliper refurbishment some months back and have recently noticed that the brake fluid level in the reservoir drops when I use the car and then rises again when the car is cold. It has overflowed out of the reservoir before. I thought might be air in the system but have bled the brakes twice and the brake pedal is not soft. Am I worrying for nothing?
Sounds like a bad master cylinder, seals shot.