What a great car to spend time with the grandson on!!!

I have a few ideas, forgive me if I cover the basics, you gave me no idea as to your level of experience. If I explain things too simple, I am not being condescending - just thorough...

What were you catching the fluid in??

The parts stores sell an inexpensive (under $10) bleed kit, It has several nipples to fit different makes of cars, a 12" piece of clear 1/4" hose, and a small lidded container with a "dipstraw." A dipstraw is a small bit of hose that goes to the bottom of the container.

If you were just pumping into an open container, and the end of the hose was in the air (not submerged in fluid) then air would work its way back up the hose into the system.

Some folks use a pop bottle and have the hose submerged in fluid in the bottle - that works too.

If there was no drop in the fluid, then I have to conclude that the master cylinder may be shot.

Both times that I bled the brakes, on two different cars, I had to replace the Master cylinders with rebuilt units. When one pumps the brake with the system open, the pedal usually goes further than normal. Within the master cylinder, the O-rings wear a ridge, and sludge builds up and when you press beyond the ridge the O-ring fails.

Also, if the fluid has not been changed for a while, the fluid absorbs moisture. This will also then cause the moisture to sit at the bottom of the master cylinder and corrode, forming another location for the O-rings to fail.

Basically, when I am bleeding the system, I can see the color of the fluid change (the old fluid is sometimes a bit darker) and also, there will be bubbles pushed down the hose. Pump until ther are no more bubbles.

For every cup of fluid you pump through, there will be one cup less in the reservoir.

Hope this helps a bit, maybe others will have more input....