1998 Buick Park Avenue Owner's Manual - Page 303

Your brake master cylinder reservoir here. It is filled is with DOT-3 brake fluid. There are only two reasom why the brake fluid level in the reservob mightgo down. The first is that the brake fluid goes ~ Q Wto an acceptable Bevel during n d brake W g wear. When new linings are putn, the fluid level i goes back up. The other reason is that fluid is Bedung out of the brake system. If it is, you ~ h ~havelYQWbrake ~ d system fixed, since a leak means that sooner or later YQIX brakes won't work w d , or won't work at al l.