Why when u push on break something clicks and.

Your possibilities here could be the brake master cylinder push rod adjustment or the brake switch-inspect and let me know what you find.

That indicates a leak in one half of the hydraulic system. The leak can be external meaning there's fluid dripping on the ground and the fluid level is going down in the reservoir, or it can be an internal leak inside the master cylinder. With an internal leak there will be no loss of fluid and no visible leakage outside the car. Don't confuse a low fluid level with a "not full" reservoir. The fluid level will go down over time as the front brake pads wear. That is normal and acceptable.