brake pedal goes almost to floor
 

pumping pedal does not bring it up any higher, pedal hard not spongy, car stops very well with moderate effort....anybody want to take a shot at this one? thanx in advance

If you can find no signs of leaks at the wheels or along the lines, the problem is most probably the master cylinder. If upon inspection the cylinder is not pitted it will rebuild well, but a rebuilt might be your best bet.

Good luck,

Brake pushrod behind the booster has an eccentric adjuster for pedal travel free play length.
The proper adjustment is with the Index mark on eccentic bolt head facing rearwards. Check that first...

Happened to me once on a 380 sl
 

It was a leaking vacuum booster. Do you hear any air escaping or a whooshing sound as you apply the brakes? Do you get good "pedal" after driving for a few minutes then as you brake it gets progressively worse?

Other than that it's probably the master cylinder-not something to let go without immediate fix.

J. Boggs