1994 Chevrolet S10 Pickup Owner's Manual - Page 247

Brakes Brake Master Cylnder Your brake master cylinder is here. It is filled withDOT-3 brake fluid. There are only two reasons why the brake fluid in your master cylinder level might go down,The first is that the brake fluid goes down to an acceptable level during normal brake lining wear. When new linings are put in, the fluid level goes back up. other reason is that fluid is leaking outthe The of brake system.If it is, you should have your brake system fixed, since a leak means that sooner or later 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. you addfluid when your linings are worn, then If you'll have too much fluid when you get new brake linings. should add You (or remove) brakefluid, as necessary, only when work done on the brake is hydraulic system. Refer to the Maintenance Schedule to determine when to check your brake fluid. See "Periodic Maintenance Inspections" in the Index. 6-29