My brake pedal slowly drops all the way down when I apply pressure.?
There are any number of reasons that a brake pedal gets spongey or sinks like that, but most typically one looks for a leak or a bad master cylinder. Now as to seeing no leak, it would not be necessary for there to be a puddle of brake fluid on the floor to have a leak. Typically what one sees is some dampness around the wheel cylinders (on drum brakes) or the calipers (on disk brakes) and that dampness will accumulate brake dust. You can pull each wheel and look for that. Essentially the system works like this: You have a master cylinder, usually mounted on the fire wall in your engine compartment and the brake fluid reservoir sits on top of it. (You can also look for dampness and accumulated dirt trapped in it there which would be indicative of a bad master cylinder). As the name implies, the master cylinder is a cylinder with a large piston inside and that piston is operated by your brake pedal. You push on the pedal, the piston moves forward, and drives brake fluid through the line
