no brakes

My 76 Corvette was outside (covered) last fall while building a new garage.  When I put it away the brakes failed.  I "figured" it was a caliper.  When I checked the master cylinder the front was way down.  I added brake fluid.  But, when I pump the brakes the fluid doesn't go down.  I checked each wheel caliper and see no fluid.  Could the master cylinder have gone? Is there a way to check this out?  Many thanx,

Bob D.  

Sounds like the master cylinder has gone bye-bye, but I'd make a really thorough inspection of the calipers again just to be safe.  

Have you tried to have the brakes bled.  Sometimes this is the best way to start a diagnosis.  Start with the right rear brake since it is farthest away from the Master Cylinder.  Have somebody pump the brakes until they feel the pedal pump up, ten times should do it and have them hold down the pedal after it has pumped up. Crack the right rear bleeder AND DON'T LET OFF THE BRAKE PEDAL TILL YOU CLOSE THE BLEEDER BACK!!!  At any rate if you have done this right you should see air in the fluid as it gushes out.  If you don't get any fluid start checking the lines from the cylinder to the proportioner valve or valves then on to the wheels. Old Brake lines will rust through especially if a car is covered and left out in the open as moisture will condense on and in the lines due to lack of flowing air.  I've seen it happen as many times as I have seen Master Cylinders go bad

RedCorvette86  
Corvette's Should only come in "Torch Red" (U1U)