2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 247Get this manual
FRONT AND REAR BRAKES EBS00402
CAUTION:
Disc brake components rarely require disassemblyDO NOT: disassemble components unless absolutely necessary; use solvents on internal brake components; use spent brake fluid for cleaning; (use only clean brake fluid) allow brake fluid to come in contact with the eyes, as this may cause eye injury; splash brake fluid onto painted surfaces or plastic parts, as this may cause damage; disconnect any hydraulic connection, as this would require the entire brake system to be disassembled, drained, cleaned, properly filled and bled after reassembly