Brake pedal problem

That is difficult to say without more information. Under most circumstances I would tend to say no, but there is nothing present for me to go on. Can you relay to us the circumstances?

I purchased this car about 7 months ago. Prior to that, it had been in storage in a barn.
Recently, the brake pedal is OK when first applied, however if I let up on the brakes (not completely) the pedal starts getting very soft and going almost to the floor. If I take my foot off completely then apply the brakes again, it is fine.

That helps a lot, thanks for the clarity. The replacement of the master cylinder is indicated in this case, you are right. Age and sitting has done the original master cylinder in so replace it, bleed the brake system and drive it like it's stolen (just kidding about the stolen part) Happy new year.