MAINTENANCE 4.12 EVERY 1000 OPERATING HOURS OR EVERY 6 MONTH High-Strength Bolt Connections (continued) Crawler Carrier Check condition and fastening of guide wheels (01), stop plates (03) and rollers (06 and 09), illust. Z 20618. Legend for illust. Z 20618: (01) Guide wheel (02) hydraulic track tensioning cylinders (03) Stop plates for guide wheel sliding blocks (06) Support rollers (09) Bottom rollers 409