1996 Chevrolet Astro Owner's Manual - Page 238

To Check Brake Fluid You can check the brake fluid without taking off the cap. Justlook at the windows on the brake fluid reservoir. The fluid levels should be above MIN. If they aren't, have your brake system checked to see if there is a leak. After work is done on the brake hydraulic system, make sure the levels are above MIN and below the top of each window. What to Add When you do need brake fluid, use only DOT-3 brake fluid - such as Delco Supreme 11 (GM Part No. 1052535). Use new brake fluid from a sealed container only, and always clean the brake fluid reservoir cap before removing it. @ NOTICE: Don't let someone put in the wrong kind fluid. For of example, justa few drops of mineral-based oil, such as engine so oil, in your brake system can damage brake system parts badly thatthey'll have to be replaced. Brake fluid can damage paint, be careful not to spill brake so fluid on your vehicle. If you do, wash it off immediately. See "Appearance Care" in the Index. 6-30