ok guys heres my problem.
i was driving the culprit car the other day (79 olds ninety eight)
when i went to push the brake to stop the parking brake warning light came on and the brakes got soft as if the car had manual brakes.

i checked the brake fluid, and the vacuum hoses they were all fine.
what could be the problem?
and why did the E-brake light come on? (it still is on, it stays on after you start the car.)

 

That "E-Brake" lamp doubles as a brake system warning light. There is a switch in the proportioning valve that will turn on that light whenever there is excessive pressure differential between the front and rear brake systems.

Chances are you are losing hydraulic pressure on one end of the car. By your description it may be the front end, since the rear brakes don't usually apply a lot of stopping power - most of it is done on the front axles.

I'd take a very close look at teh calipers and wheel cylinders, lines, hoses, bleeders, etc. If you don't find any external leakage, you may have a failed master cylinder, allowing brake oil from the front system to bypass the seals and leak into the rear system. Once you release the brake the oil would tend to flow right back to where it belongs, but you still get no hydraulic pressure on one half of the system.