1993 Cadillac Eldorado Owner's Manual - Page 303

BRAKE M!XSTERCYLINDER Your brake master cylinder is here. Itis filled with DOT-3 brake fluid. 4.9 Liter 4.6 Liter (Northstar) There areonly two reasons why the brakefluid level in your master cylinder might go down. The first is that the brake fluid goes down to an acceptable level during normal brakelining wear. When new linings are put in, the fluid level goes back up. The other reason that fluid is is leaking out of the brakesystem. If it is, you should have your brake system fixed, since a leak means that sooner later or your brakeswon't work well, or won't work at all. So, it isn't a good idea to "top off" your 289