While driving back from a local trip, I noticed the brake pedal in my 1982 Ford Granada got closer and closer to the floor as I applied the brakes. I was lucky to get it home without a collision. I had to drive extremely slow and do a lot of down shifting to slow down. I noticed the fluid reservoir was nearly empty. I refilled it, ran the engine and pumped the brakes many times, but still, the pedal was too close to the floor. I had the master cylinder replaced about 4 or 5 years ago. Could this be caused by a fluid leak? Excessively worn brake pads?
Fill the master cylinder with brake fluid, pump the brake pedal rapidly, and look for the leaks.
Pump the pedal as @Tester recommends. Look for a puddle under the car. Also look at the inside of the tires.
If there is a wet area on the inside of the tire, you most likely have a leaking brake cylinder.
If I remember right, the 82 Granada had drum brakes on the rear and disc’s up front.