Will a overfilled master cylinder cause soft brake pedal?

Yes, an overfilled master cylinder can cause a soft brake pedal. When the fluid level exceeds the maximum limit, it can lead to excessive pressure in the brake lines, potentially causing air to enter the system or fluid to overflow, both of which can reduce braking efficiency. This results in a spongy or soft brake pedal feel. It's essential to maintain the correct fluid level to ensure optimal brake performance.