1993 Chevrolet Corvette Owner's Manual - Page 271

Service & Appearance Care Brake Master Cylinder Your brake master cylinder is filled with DOT-3 brake fluid. There are only two reasons why the in brake fluid level your master cylinder might go down. The first is that the brake fluid goes down to an acceptable level during normal brake lining wear. When new linings are put in, thefluid level goes back up. The other reason is that fluid is Iealring out of the brake system. If it is, you should have your brake system fixed, since a leak means that sooner or later your brakes won't work well, or won't work at all. So, it isn't a good idea to "top off" your brake fluid. Adding brake fluid won't correct a leak. If you add fluid when your liningsare worn, then you'll have too much fluid when you get new brake linings. You should add (or remove) brake fluid, as necessary, only when work is done on the brake hydraulic system.