Upper tie bar bolt. A threaded rod with a drive head (such as hex, 12 point, torx, etc) on one end used to secure the Engine Support Rod to it's mounting point. Accessory Drive Belt Idler Pulley Bolt. Radiator Support Tie Bar Bolt. Metric HEAVY HEX Flange HEAD REDUCE. Accessory Drive Belt Idler Pulley. Bracket. Engine Support Rod. HEAVY HEX Flange HD REDUCED Body. Radiator Support Tie Bar.