1994 GMC Suburban Owner's Manual - Page 290

To Check BrakeFluid You can check the brake fluid without taking off the cap. Just look at thewindows 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 at Delco Supreme 11 (GM P r No. 1052535). Use new brake fluid from a sealed container only, and always clean the brake fluid reservoir cap before removing it. @ NOTICE: 0 Don't let someoneput in the wrong kind of fluid. For example, just a few drops of mineral-based oil, suchas engine oil, in your brake system can damage brake system parts so badly that they'll have to be replaced. Brake fluid can damage paint, so be careful not to spill brake fluid on your vehicle. If you do, wash off immediately. See it "Appearance Care" in the Index. 0