w140 brakes trouble

[rekatt]

Hello there.
Today I started up my 95 S350 and after idling like 2 minutes I put it in reverse and drove back about 20 feet to get it out from my yard in the street.
What really surprized me was when I tried to brake, the brake pedal was like stone, and even though I pressed hard I still couldnt move them even slightly.
I had to take the shifter out of Reverse and I hit the handbrake, and that stoped the car from hitting the wall behind me.
After this I pressed tried to press the regular brake pedal and it made a noise like something releasing air and then it went all the way down easily.
After pumping the brake pedal about 3-4 times it started to work again.
I drove the car for about quarter mile and hit the brakes all the way down several times, and everything seemed to work fine.

Is my W140 doing me a favor and warning me to change anything in the brake system, maybe a new pump or something?!

Thanks