1997 Chevrolet Astro Owner's Manual - Page 288

Brakes Brake Fluid have your brake system fixed, since a leak means that sooner orlater 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 linings areworn, then you'll have too much fluid when you get new brake linings. You should add (or remove) brake fluid, asnecessary, only when work is done on the brake hydraulic system. If you have too much brake fluid, it can spill on the engine. The fluid burn if the engine will is hot enough.You or others couldbe burned, Your brake master cylinder reservoir is here. It is filled with DOT-3 brake fluid. There are only two reasons why the brake fluid level in the reservoir might go down. The first is that the brake fluid goes down to an acceptable level during normal brake lining wear. When new linings areput in, the fluid level goes back up. The other reason is that fluid is leaking out of the brake system. If it is, you should and your vehicle could be damaged. brake Add fluid only when work is done the brake on hydraulic system. Refer to the Maintenance Schedule to determine when to check your brake fluid. See "Periodic Maintenance Inspections" in the Index.