1995 GMC Sonoma Owner's Manual - Page 245

Refer to the Maintenance Schedule to determine when to check your brake fluid. See "Periodic Maintenance Inspections" in the Index. To Check Brake Fluid You can check the brake fluid without taking the cap. Just look at the off windows on the brake fluidreservoir. The fluid levels should above MIN. be If they aren't, have your brake system checked toifsee is a leak. there After work is done on the brake hydraulic system, make sure the are levels above MIN and below the top each window. of 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 containeronly, and always clean the brake fluid reservoir cap before removing it . @ 6-27