1998 GMC Sonoma Owner's Manual - Page 280

Open the cap labeled WASHER FLUID ONLY with the washer symbol on it. Add washer fluid until the tank is full. Brakes Brake Fluid NOTICE: 0 When using concentrated washer fluid, follow the manufacturer's instructions for adding water. a Don't mix water with ready-to-use washer fluid. Water can cause the solution to freeze and damageyour washer fluid tank and other partsof the washer system. Also, water doesn't clean aswell as washer fluid. a Fill your washer fluid tank only three-quarters full whenit's very cold. This allows for expansion freezing occurs, if which could damage the tank it is if completely full. 0 Don't use engine coolant (antifreeze) in your windshield washer. can damage It your washer system and paint. 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 nolmal brake lining wear. When new linings are put in, the fluid level goes back up. The other reason is that fluid leaking out is of the brake system. If it is, you should have your brake L 6-30