Suzuki GRAND VITARA XL-7 Owner's Manual page 116

BRAKES PIPE/HOSE/MASTER CYLINDER 5A-9
4) If measured depth is out of above specifications, adjust to
specifications below by turning adjusting screw of piston rod.
Special tool
(F) : 09952-16021
Depth "d" of piston rod for adjustment :
16.3 – 16.6 mm (0.642 – 0.653 in.)