Usage:
Caterpillar Machines Powered By 3408 And 3412 Engines
Description of Change: New tapered roller bearing water pumps are now used on 3408 and 3412 Engines. The seal contact surface of the shaft is now induction hardened which improves wear resistance at the point of seal contact. The seal material has been changed to a siliconized graphite that is more resistant to wear and less prone to deposit formation.
A new accessory drive idler shaft is used with the new water pumps. An additional hole has been added to the idler shaft to provide improved lubrication to the water pump tapered roller bearings.
Adaptable To: The new 117-4956 Water Pump Group is used on 3408 Engines. The new 117-4955 Water Pump Group is used on 3412 Engines. The new pumps can only be used on engines that have the new 117-9712 Accessory Drive Idler Shaft. The former shaft does not provide sufficient lubrication for the new pump. The new water pump groups and idler shaft are effective with 3408 (48W38946) Machine Engines, and 3412 (73W16055) Machine Engines. Engines prior to these serial ranges should be serviced with the appropriate remanufactured water pump.