It could be something very simple. Check the metal lines that connect to the master cylinder. They can rattle loose from the engine vibrations. Then check the connections to the calipers. If these are all good and tight, then go ahead and drop the hundred bucks on a master cylinder. While you are at it change the rubber brake lines if you havent done it yet.

Update
 

Replaced Master cly. and checked front pads.
Pads were ok bleed front brakes to remove all old Brake fluid.
Used Dot 4.
Will get to back brakes tomorrow.

I've worn out a few master cylinders.

In the early stages of failure, the master cylinder seals usually hold under high pressure, but seep slowly under low pressure. That is, if you press hard, the brakes work fine, but when you release the pressure, the pedal slowly sinks to the floor.

If you keep driving in this state, you will wear the seals to the point where the pedal always does go to the floor. But it doesn't start that way.

But the distinction between master cylinder and wheel cylinder failure is easy to spot. The latter causes the fluid level to go down faster than pad wear could cause.

Cool, the problem is 90% fixed.:cool:

Up Date Problem Fixed
 

Ok I checked all brake pads all were ok.
Replaced the master cyl.
Changed the brake fluid. (Used Dot 4)
Took car out on interstate and when it came time to stop I had good
brakes so problem is fixed. Thanks for the help.

Hmm, note post 5.;) Glad you got it fixed.:cool:

dont forget post #3, hattie.

heh heh

tom w

How could I, you beat me to it!:D