1993 Oldsmobile 88 Owner's Manual - Page 242

Brake Master Cylinder Your brake master cylinder is here. It is filled with DOT-3 brake fluid. There are only two reasons whythe brake fluid level your master cylinder in might go down. The first is that the brake fluid goes down to an acceptable level during no& brake bring wear. When new^ linings are put in, the fluid level goes back up. is The other reason that fluid is leaking f out o the brake system.If it is, you should have your brake system fixed, since a leak means that sooner later or your brakes won't work well, won't or work atall. So, it isn't a good idea to "topo r ' your brake fluid.Adding brake fluid won't correct aleak. If you add fluid when your linings are worn, thenyou'll have too much fluid when get new brake you linings. You should add (or remove) brake fluid, as necessary, only when work is done on the brake hydraulic system.