Yet another goddamn problem with the Kia and brakes

I thought I was supposed to help someone with their computer today, but
as it turns out, I didn't have any pressing need to go anywhere. I was
wanting to get some other stuff done though.

So this afternoon, I went out to the car and started it up. I hate
having to fight this car to get it started, but it took more than 3
starts to get it going. I know the fuel tank isn't venting right because
the fuel backs up in the fill thingy and pops the nozzle to off which
requires me to wait for it to flow down into the tank every 7 tenths of
a gallon or so.

Anyway, I back up and get to the end of the driveway and begin to make
my turn to go out on the road and I press the brake pedal. Only it goes
squish all the way to the floor.

I don't think that's supposed to happen.

Anger and anxiety set in as I pull it back into place, and do a few more
squish to the floor pressings and the brake fluid light comes on. Just
F-ing great.

I have some more fluid around here, left over from last year when I had
the rear brake system worked on. I didn't think to have the rest of the
brake lines inspected then, but they weren't giving me problems then.

I hope this is just some stupid brake line that's not extortion-rate
priced to replace. If it's a master cylinder or something... I would
hear an audible squish sound from outside when I pressed the brake
pedal, like how air is forced out of a bellows or some other similar air
bladder. So perhaps the fluid is squirting out of a damn faulty line.

If I had tried to go somewhere with things like this, I'd have had
almost no way to stop. I can't drive it like this.

Dammit.