94 Honda Accord brakes failed

Today my wife took the 94 Honda Accord and fortunately was nearly stopped when suddenly she had no brake pedal left and hit the back of a large pu truck. No damage to the truck, but now we have a nasty dent in the hood where it impacted with the truck ball hitch.

The driver of the other vehicle was satisfied that he had no damage. He even got in the Honda and surprisingly exclaimed, "you've got brakes". The car was then driven back home. Then I drove it to work.

Here's some history. I had the ABS light come on about 6 weeks ago. I checked the brake fluid and had to add about 8 ounces from a 12 oz. can of brake fluid. Subsequently one day I was backing out of the drive way and as I pushed on the brake pedal to stop and go forward the pedal went to the bottom and I quickly pumped it and the pedal came back up. I have driven the car daily and no problem until this morning.

Question: What is causing the brakes to fail on occassion but not normally? Need some help quickly because I now know that the car is unsafe to drive. Are there ever spots of brake fluid on the ground? does the top ever pop off the top of the fluid resivoir? there is probobly just air in the system, i would get the brakes blead to begin with. The loss of 2/3 of your reservoir fluids leads me to believe you have a leak. You filled it 6 weeks ago, hows the level now? If it's low again, you night have a leak in one of your brake cylinders. Look on the inside of your wheels and see if you have any wet spots to indicate a leak. If it's wet, start looking at that wheel cylinder. Good Luck and let us know what you find.