PISTON 3T7399 - Caterpillar

D379, D398, D399, G379, G398, G399 EnginesSUPPLEMENT: 02/20/78SERVICE MAGAZINE, JANUARY 9, 1978, PAGE 6.In the article "Improved Seal Used Between Impeller And Bearings On Water Pump Shaft" change the 1.82" dimension shown in the Illustration on Page 6 to read 1.812".--------------- END SUPPLEMENT ---------------Description of Change: An improved seal is used between the impeller and the bearings on the water pump and auxiliary water pumps for the above models. The new seal has components made of rubber and ceramic and is similar to the seal used in the water pumps for the 3400 Series Engines. The new seal is more reliable (less probable to leak) than the former seal. New housing assemblies and shaft assemblies are used with the new seal. The impellers were changed to make assembly and disassembly of the seal easier. The part numbers of the impellers did not change.Adaptable As: Direct replacement when the new parts are used together. A modification can be made to the former housing assemblies so the new seal and shaft assemblies can be installed. See "INSTALLATION". INSTALLATION: The bore in the former housing must be machined as shown in the illustration if the new seal and shaft are to be installed.
4L8800 and 6N8983 Water Pump Groups. For identification of separate parts, see the chart.
2N955, 3N4305 Auxiliary Water Pump. Use clean water only as a lubricant to make the assembly of the seal easier.1. Put 7M7456 Loctite on the outer side of the adapter and in the housing bore. Install the adapter in the bore.2. Carefully install the 6N5476 Ring and the 6N5475 Seal in the pump housing with the polished (very smooth) face of the ring toward the 6N4743 Seal Assembly.3. Remove the spring from the 6N4743 Seal Assembly. Put water on the inner diameter of the seal assembly and carefully push the seal assembly on the shaft until the seal faces make light contact.4. Install the spring and the impeller.