The level of the brake fluid in the reservoir will continue to decrease as the pads and rotors wear and more and more fluid fills the pistons in the calipers. Pressing the pistons back into the calipers when replacing the pads will refill the reservoir. If you have topped off the reservoir due to a low level light, you may have an overflow of the reservoir. If your rotors are near the minimum thickness and the pads are completely worn, you can get a low level light without a leak. Re-check the level after the pads and rotors are replaced and the reservoir is again near the max level. If it is lower than normal at this point, you should check for a fluid leak if you haven't already spotted one when replacing the brakes.
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Scott
1991, 252K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
Class II hitch, Silver award at the SHOklahoma Car Show