The brakes were exactly the same before I did a brake flush. I flushed them by bleeding the fluid from each wheel into an oil catch can. I made sure to shut the valve before my helper would let off the pedal. I'm nearly 100% sure it's not air in the system. I do have enough fluid. In order to stop the car even under 10 MPH I have to push the pedal all the way down to even get close to slowing. This car is new to me;however it sat for around ten years in my father's driveway,so I know it's not like the person before me scewed around with anything. Does anybody know what can possibly be wrong?

 

Probably has air in the MC.

Gotta take it off and bench bleed it. NO AMOUNT of bleeding it with it still on the car, will get the air out of it. You can pump 100 gallons of fluid through it and make not the slightest difference whatsoever.

Gotta take the MC off and bench bleed it.

 

Car sat for 10 years...what could possibly be wrong? If you haven't replaced everything I'd start there if the car is a keeper. Every piece of the system is 20+ years old and add 10 years of sitting to that.
If you want to isolate the problem right now start by buying 2 plugs that screw into the MC. Plug the MC and see what you get. If the pedal isn't rock hard you have air in the MC or a bad MC.

 

Possible brake booster failure.

 

^ This

 

As cheeeeeeeeep as brake parts are, not a bad idea, except that a bad booster won't make the pedal go to the floor and not work the brakes. A bad MC will however. A bad booster makes the brake pedal hard, like the engine isn't running, since when it goes bad, it doesn't boost. Failing to boost, and/or causing a vacuum leak from the same cause (broken rubber diaphragm), is its only possible failure. (as far as a working one, on the car, going bad)

Problem could well be the MC though.

Of course when you put on a new MC you'll be facing the same requirement as above. Gotta bench bleed it before you put it on.

 

Stock third gen master cylinders are a step bore design because the factory brake calipers are low drag from the factory. A step bore master cylinders has two different bores. Larger bore for volume and a smaller bore for pressure. It also has a 100 lbft valve built in. Once the brake pedal is pressed, the large bore supplies the extra volume needed to fill the stock low drag calipers up with fluid and gets the brake pads up against the brake rotor. Once the brake fluid pressure reached 100 lbft, the valve in the master cylinder activates and allows the smaller bore to add pressure to the fluid to force the caliper pistons to clamp against the pads to stop the car.

If this valve fails in the open position, it will not get sufficient amount of fluid to the brake calipers and you will have long pedal travel before the brakes start to work.

Since brake fluid is hydroscopic (attracts water), it may have corroded the bypass valve in the master cylinder. I would suggest a new or rebuilt master cylinder first, bench bled correctly. Bench bleeding a step bore master cylinder is more sensitive to bench bleeding because of the built in bypass valve, so it needs to be done correctly.